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What Constitutes a Normal Semen?
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What Constitutes a Normal Semen? Henry C. Folk, M.D., and Sherwin A. Kaufman, M.D.
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T.m STANDARDS established for normal fertile semen vary with different observers, depending upon what each worker in the £eld regards as important. Some investigators have emphasized sperm morphology as the chief factor in evaluating a specimen. 12 • 20 Others stress the importance of the sperm count-and even here there is a difference of opinion as to whether count per unit volume or the total count is .the more important. 1 • 14 • 25 Still others feel that motility is the prime factor, and one investigator states that the total number of moving spermatozoa in the entire ejaculate is the chief index of fertility. 2 Moreover, there are varying standards for each of these separate aspects of semen analysis.
MORPHOLOGY A good deal of controversy has arisen regarding the importance of sperm morphology ever since Williams and Savage, in 1925, reported a high correlation between the breeding record of bulls and the morphology of their spermatozoa. These authors concluded that "morphology of the head of the sperm constitutes the greatest single source of information as to the £tness of the cells for reproduction." A few years later, Moench20 applied this type of study to the human, and was even more specilic in his conclusion that when the number of abnormal forms is "above 25 per cent, there is always sterility." Kleegman10 analyzed the semen of 50 men where conception took place at will and normal children were born. Only in a single case did the abnormal forms reach as high as 25 per cent. A similar series of 25 men whooe wives conceived without difficulty was studied by Weisman, 23 From the Department of Obstetrics and Gynecology, Beth Israel Hospital, N. Y. 489
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who found that the number of abnormal forms did not exceed 20 per cent in any case. And in England, Lane-Roberts et al. analyzed groups of fertile and infertile men, and stated that "no man whose reproductive record could be regarded as satisfactory produced more than 18 per cent of spermato_zoa with abnormal head forms." Somewhat different results, however, were obtained by Hotchkiss, Bruner and Grenley in a study of 200 men whose wives were pregnant and were delivered of normal children. In their series, 5 cases had 25 per cent or more abnormal forms, the highest being 32 per cent. Jeffcoate reported 6 cases of pregnancy with the husbands' sperm specimens exhibiting over 50 per cent abnormal forms in each case. MacLeod 16 is at present making a careful study of a large group of men whose wives are pregnant. Morphologic analysis of 874 of his cases revealed that as many as 39 per cent of the specimens exhibited more than 20 per cent abnormal forms; 17 per cent of the cases had more than 30 per cent abnormal forms; and 3 per cent had higher than 50 per cent abnormal sperms, the highest being 80 per cent!
NUMBER OF SPERM Equally controversial has been the question of the sperm count in sterility, particularly since Meaker, 17 in 1934, stated that in his experience "no pregnancy has occurred in cases where the sperm count was below 60,000,000." Actually, Meaker has since modified this statement to the extent of feeling that "counts considerably below 60,000,000 are not incompatible with the capacity to procreate, particularly if the morphology of the spermatozoa is good." 18 There have been a number of reports substantiating the view that fertile matings may take place in spite of definite oligospermia. In the series studied by Hotchkiss et al., 52 of the 200 fertile men had counts less than 60,000,000 per cc. In Kleegman's 10 series, however, all of whom were of very good fertility, only 1 case exhibited a count less than 60,000,000 ( 35,000,000 per cc.). MacLeod 14 obtained complete histories on 140 sterility cases in which 24 pregnancies eventually took place. Although the majority ( 60 per cent) of the husbands in the pregnancy group exhibited good semens, there was a group of 7 pregnancies in which the semen specimens were poor, inasmuch as their sperm counts averaged only 31,000,000 per cc. One of these specimens was as low as 5,000,000 per cc. with very poor motility, yet pregnancy took place. In MacLeod's 16 series, analyzing the sperm counts of
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1000 fertile men, he found that 290 of them ( 29 per cent) had counts of less than 60,000,000 per cc.; 16 per cent had less than 40,000,000 per cc.; and 2 per cent ( 20 cases) had less than 10,000,000 per cc., the lowest count being 1,000,000 sperm per cc.! The relative importance of the total count versus the count per cc. has also received considerable attention. MacLeod and Hotchkiss, in a study of 1500 cases of sterile marriage, emphasized the sperm count per unit volume rather than the total count. On the other hand, Belding felt that a low count in itself does not necessarily indicate poor fertility. He emphasized the total number of spermatozoa as a "more accurate method of expressing results than the number per cubic centimeter." The total count was also favored by Wilhelm, who felt it was a more reliable index of fertility.
MOTILITY The question of sperm motility has likewise been the source of much debate. On the one hand, Farris states that "the index of fertility in man is based on the number of moving sperm in the total ejaculate." Taking the opposing view, Moench 21 states that motility is "no criterion for the fertilizing power of a spermatozoa." He points out that some sperm may have temporary immotility, that cell collision may impart apparent motion to some cells, and that some abnormal spermatozoa may be just as motile as normal looking sperm, and may retain their motility as long or even longer. Keshin and Pinck also report that specimens containing a large percentage of abnormal forms may remain motile as long as normal spermatozoa, whereas Weisman24 holds a contrary opinion. Pollak studied the relationship between head abnormalities and motility. He found that giant heads are generally sluggish and that sperm with a displaced or absent centrosome are often immotile. On the other hand, he found that when the sperm head is smaller than normal, motility is preserved. PRESENT STUDY Because of such varying reports and lack of standards, it was felt that the question of what constitutes a "normal" semen could be answered only by a study of a very carefully selected group of cases, namely, men of unquestionable and repeatedly proven fertility. We assumed that any semen capable of producing 2 or more normal children, with no history of spontaneous miscarriage, is definitely a "normal" specimen. Our object was then
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to determine the characteristics and variations found in such carefully selected cases. A preliminary report of this study, comprising 40 selected cases, was published in 1946.9 Semen analysis was carried out on single specimens from 100 men whose wives ( 1) were pregnant at the time of study, ( 2) have now had two or more normal children, and ( 3) have never had a spontaneous miscarriage. The wives of these men were all indigent patients of the Beth Israel Hospital prenatal clinic.
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FIFTY-TWO PLANNED PREGNANCIES
(Coitus One to Four Times per Weelc) 15
12 ~ 9 a
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6
14
3 2
3
4-5
Months FIGURE
1.
Duration of exposure before conception.
Further evidence regarding the fertility and sex habits of these patients was obtained by means of a detailed questionnaire. Of the 91 women who have replied, 39 ( 43 per cent) termed their latest pregnancy an "accident." Since all in this group used some method of contraception (chiefly withdrawal or condom), a pregnancy as a result of an "accident" in itself indicated a high degree of fertility. The other 52 women had "planned" the pregnancy, practically all having practiced contraception previously (chiefly by use of the condom in this group). Of these 52 planned pregnancies, 15 became pregnant after one month of trial, 10 after two months, 15 after three months, 6 after four to five months, and 6 longer than five months but
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within a year (Fig. 1). That is, over. three-fourths of the women who planned their latest pregnancy conceived within three months. The frequency of intercourse in this group varied from one to four times weekly, the majority indicating twice a week. Practically all of the 91 cases in which a detailed history could be ascertained, therefore, gave further proof of good fertility. METHOD OF OBTAINING SPECIMENS
Each of the wives, in the course of regular prenatal clinic visits, was provided with a clean, dry, wide-mouthed glass bottle with a cork stopper, and given the following written instructions: The husband was to abstain from sexual relations for a minimum of three days before the date of collection. On the morning of the wife's next prenatal clinic visit, the husband was to produce a semen specimen either by masturbation into the bottle or by coitus, withdrawing just before emission and ejaculating directly into the bottle. No specimen was accepted if there was any reported loss during collection. All specimens were carried directly to the clinic by the wife in her handbag, the exact time of collection being noted on the bottle. More than half the specimens were examined within three hours of emission, the rest within four hours. METHOD OF ANALYSIS
Standard clinical procedures were used in all cases, observations being made at room temperature. Each specimen was first grossly examined to note the general appearance, amount of liquefaction, and relative turbidity. Viscosity was tested by stirring the specimen with a wooden applicator and noting the tenaciousness of the fluid upon withdrawal of the stick. The specimen was then transferred to a clean, dry, graduated glass cylinder for volume determination. Motility was studied by placing a large drop of semen on a glass slide with a cover slip, and using an ocular provided with a disc that obliterates all but one-quarter of the field. Where the number of sperm were very great, a disc with a more restricted field was used. The number of motile cells in the narrowed field was counted as rapidly as possible, and then the total number of cells in the same field was counted. The ratio of the former figure to the latter gave the percentage of motile cells. Two or three such quarterfields were thus examined, and the average taken, with the exclusion of
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extreme variations. Motility studies were done at approximately three- or four-hour intervals during the first twelve hours, and again at the end of twenty-four hours. The quality of motion was judged as good, fair, or poor, "good" being active, rapid movements across the field. The sperm count per cubic centimeter was determined, after thorough shaking of the specimen, by diluting to 1:20 in a white blood cell pipette using a diluent of 5 per cent sodium bicarbonate solution with 1 per cent formalin. All the cells in the red blood cell field of a standard Neubauer chamber were counted, giving the count per square millimeter. From this figure, the count per cubic centimeter was computed. Two separate counts were made in each case, and the average taken. The total count was obtained by multiplying the count per cc. by the volume. Morphology studies were carried out by preparing a thin smear of semen on a glass slide. A new slide was first washed in 95 per cent alcohol to remove the thin coat of oil usually present. After preparing the smear, the slide was fixed in 10 per cent formalin for two minutes, then placed into Mayer's hematoxylin for one minute, and then immersed in warm water for one minute. Morphologic types were considered largely according to the criteria of Hotchkiss et al. Seven general groups were recognized: oval (normal), small, large, tapering, round, amorphous, and double. Two hundred spermatozoa were counted and tabulated for each case. Certain disfigurements of the tail such as angulation, coiling, or complete absence of the tail were considered as possible artifacts and were purposely omitted from the count. Microprojector tracings of the various types met are shown in Figure 1 of a previous report. 9
RESULTS The results of this study are tabulated in detail in Table 1. The age of the husband varied from 25 to 54 years, the average being .:34.2 years. The volume of the ejaculate varied from 0.5 cc. to 5.2 cc. A peak volume of from .:3.0--.:3.5 cc. was reached by .:30 per cent of the cases (Fig. 2), while the mean volume for all cases was 2.85 cc. (standard deviation 0.93). Although there were 11 cases in this series with volumes less than 2.0 cc., only 1 specimen was less than 1.0 cc. ( 0.5 cc. ) . This specimen also exhibited a relatively low sperm count (50 million per cc. ) , although the motility was satisfactory. A second specimen from this man, given three months after
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WHAT CONSTITUTES A NORMAL SEMEN?
TABLE 1.
Age Volume in cc. Per cent motility ( 2-4 hr.) Per cent motility ( 6-7 hr. ) Per cent motility ( 12 hr.) Per cent motility ( 24 hr.) Sperm count" per cc. Total sperm count" Per cent abnormal forms Per cent small Per cent large Per cent tapering Per cent round Per cent amorphous Per cent double
Summary of Findings Number
Mean
100 100 100 68 71 92 100 100 100 100 100 100 100 100 100
34.2 2.85 61.0 45.9 26.5 8.0 101.0 295.0 11.6 2.3 2.4 3.0 1.6 2.1 0.3
5.5 0.93 12.3 13.5 11.8 5.9 45.0 178.1 4.5 1.2 1.4 1.4 1.0 1.9 0.5
• In millions.
30 27 24 21
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Volume in C C FIGURE
2.
Volumes of ejaculates.
the first, showed a volume of 1.0 cc., a count of 58 million per cc., with good motility and morphology. Viscosity was abnormally high in 7 of the 100 specimens, even after many hours of standing. Two of these had a very high sperm count (over 200 million per cc. ) , 1 had a relatively low count (50 million per cc. ) , and the others had counts ranging between 90 and 135 million. All had good motility.
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Turbidity was increased in four cases. Only one of these had a relatively high sperm count ( 225 million per cc. ) . Decreased turbidity was found in 2 cases, one of which exhibited a low count ( 28 million per cc.) and poor motility. The average percentage of motile forms decreased as the time increased (Fig. 3). All specimens were examined within four hours. The motility during this interval ranged from 30 per cent in one case to 82 per cent in another, the average for all cases being 61 per cent. At the end of six to seven hours, the average percentage of motile forms for the 68 cases Cases
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46 23
26 14
71
92
60
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; 30 A. Q>
en
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Hours after Ejaculation FIGURE
3.
Duration of motility.
examined varied from 12 per cent to 70 per cent, with an average of 45.9 per cent. After twelve hours, examination of 71 cases showed a motility range of from 2 per cent to 50 per cent with an average of 26.5 per cent. After twenty-four hours, examination of 92 cases showed a range of from 0.0 per cent to 21 per cent motile forms, with an average of 8.0 per cent. Nine cases had a relatively low percentage of active forms, with no motility at all at the end of twenty-four hours. In 6 of these specimens the sperm count was reduced as well (all below 40 million per cc.). The other 3 cases had counts of 56, 60, and 150 million per cc., respectively. Moreover,
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the quality of motility was "poor" in 8 of the 9 cases, but was consistently "good" or "fair" in all the others. The spermatozoa count per cubic centimeter varied from 28 million in one case to 225 million in another. The average count for all cases was 100.7 million per cc. In 15 of the 100 cases ( 15 per cent) the sperm count was below 60 million per cc. Eleven of these had total counts below 150 million. Moreover, the volume was found to be below 2.0 cc. in 4 of the 15 cases and the percentage of motile spermatozoa was relatively low in 7 (almost half); however, the morphology was "poor" in only 1 of these cases. Follow-up of the husband with the lowest count ( 28 million per cc.) revealed no physical abnormalities and an essentially negative history. A second specimen from this man, given six months after the first, revealed a count of 48 million per cc., a volume of 2.2 cc., and 54 per cent motile cells at the end of three hours. His wife has since been delivered of a normal child, her fourth. Total cell counts varied from a low of 25 million in one specimen with a volume of only 0.5 cc., to a high of 1 billion, 80 million in another (volume 4.8 cc.). The average total count for all cases was 295 million. The total count was below 150 million in 18 of the 100 cases. Of these, 12 cases had counts less than 60 million per cc., and 6 exhibited poor motility. Morphology study revealed an average percentage of normal (oval) forms of 88.4 per cent, with a range of from 70 to 97 per cent. The percentage of abnormal forms was relatively low, the average for all cases being 11.6 per cent. In no case did the number of abnormal forms exceed 30 per cent. Three cases had more than 20 per cent abnormal forms; 2 of these had counts below 60 million per cc., and 1 had poor motility as well. Of the abnormal types, the tapering forms occurred with greatest frequency, ranging from 0.0 per cent to 7.0 per cent with an average of 3.0 per cent for all cases. Large forms were next most frequent, with a range of from 0.0 per cent to 7.0 per cent and an average incidence of 2.4 per cent. Small forms ranged from 0.0 per cent to 6.0 per cent and averaged 2.3 per cent. Amorphous types ranged from 0.0 per cent to 14.0 per cent and averaged 2.1 per cent. Hound forms averaged 1.6 per cent. Double forms (double heads or tails) were distinctly rare. They were found in only 19 of the 100 cases, with a range of from 0.0 per cent to 2.0 per cent and an over-all incidence of only 0.3 per cent.
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DISCUSSION Age
No correlation was noted between any phase of the semen analysis and the husband's age. Volume The ejaculate volumes in this series ranged from 0.5 to 5.2 cc. The absence of very high volumes appears to be of significance, particularly when judged in the light of other reports. Kleegman, 11 for example, has never seen a fertile semen with a volume as high as 10-12 cc. Of the 200 fertile cases reported by Hotchkiss et al. there were only 2 cases with volumes as high as 9.0 cc. MacLeod15 has recently made an extensive analysis of ejaculate volumes in 800 fertile men and 600 men in infertile marriage. He found that the mean volume was 3.33 cc. for the fertile group, and 3.59 cc. for the infertile group. He feels that this difference is statistically significant, particularly since comparison with other fertility-infertility series shows a consistently higher mean volume for the infertility groups. He also found that, in general, "the highest semen volumes are associated with infertile individuals who had never produced conception and whose semen is of poor quality." It should be borne in mind, however, that in any individual case, a large volume per se does not necessarily constitute an infertile specimen. In MacLeod's fertility series comprising 1000 men, the mean ejaculate volume was 3.4 cc., but there were 48 specimens over 6.5 cc., the highest volume being 9.5 cc.! In the study of ejaculate volumes, results may vary according to whether the emission was produced by masturbation or withdrawal, there being a greater likelihood of loss during collection of withdrawal specimens. The difference between our mean volume (2.9 cc.) and that of MacLeod's series (3.4 cc.) might be explained partly by the fact that in our group most of the specimens were obtained by withdrawal rather than by masturbation. In regard to relatively low volumes, 11 per cent of the cases in our present series had less than 2.0 cc. ejaculate, but only one was less than 1.0 cc. These low-volume specimens were as good in other respects as specimens with higher volume. In an analysis of 1500 cases of sterile marriage, MacLeod and Hotchkiss found "negligibly few cases in which low volume could be considered as the source of infertility." Viscosity
The significance of increased viscosity is not clear. Hotchkiss 6 believes that a "thick ejaculate hampers the progress of the sperm by mechanical obstruction." MacLeod, 13 on the other hand, has found no real correlation between high viscosity and subnormal motility, and feels that specimens showing active motility are not likely to be hindered by high viscosity in their migration into the cervical canal. In our series, 7 cases of which showed increased viscosity, there was no correlation between the thickness of the ejaculate and poor motility or count. The chief difficulty with these specimens is drawing the semen into a pipette for counting purposes.
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Turbidity No special significance could be attributed, in this series, to either increased or decreased turbidity as an isolated characteristic.
Motility Eighty per cent of the cases had an initial motility of 50-80 per cent (Fig. 4), while the duration of motility is shown in Figure 3. The average initial motility for all cases was 61.0 per cent, examination being made within four hours. This
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30 27 24 21
= 18 ~ IS 12 9
6 3
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10 20 30 40 50 60 70 80 90 100 FIGURE
Per Cent Active Cells 4. Initial motility.
corresponds rather closely to the results obtained by MacLeod 16 in an analysis of 710 fertile cases; the average motility within five hours of ejaculation in his series was 58 per cent. These motility figures would seem to indicate that our present standards for initial motility are set too high, and that what may appear to be 90-95 per cent active cells at first glance will generally prove to be considerably less when careful count is made. Farris states that "an infertile male is one possessing less than 83 million moving sperm" in the entire ejaculate. This implies that any specimen with a total count of less than 83 million is infertile, even assuming 100 per cent motility. Yet in our series alone, there are 6 cases with total counts below 83 million, and all are specimens from definitely fertile individuals. However, in our series, there was a definite correlation between a lowered motility (less than 45 per cent active forms on initial examination) and other aspects of the analysis; 6 of the 9 cases with decreased motility had reduced sperm counts and almost all had poor quality of motion as well.
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Count
Perhaps the greatest source of erroneous impression in regard to the fertilizing capacity of a semen specimen is the sperm count. One even hears the term sperm "count" being used almost synonymously with sperm "analysis," as if it were the only factor to be considered. As with motility, our present standard for "normal" sperm counts appears to be too high. We have already mentioned some of the numerous reports in the literature concerning cases where pregnancy took place with relatively low counts. These should not be thought of as isolated instances. In our own group of 100 men of unquestionable fertility there were 15 specimens with counts below 60 million per cc., almost half of these being below 40 million per cc. In Hotchkiss' group of 200 fertile men, 25 per cent had counts below 60 million per cc., and in MacLeod's 16 recent study of 1000 fertile men, 29 per cent had fewer than 60 million spermatozoa per cc. Whether the difference in these figures represents degrees of relative fertility is a matter of conjecture. The main point is that our arbitrary standard of 60,000,000 is too high. We have found, however, as MacLeod has pointed out, that as the sperm count falls below 60 million per cc., other "deficiencies" begin to appear with increasing frequency. Of the 15 men in our present series whose counts were below 60 million, almost half had deficient motility, three-fourths had total counts below 150 million, and one-fourth had ejaculate volumes below 2.0 cc. The morphology was "poor" in only 1 of these cases, however. The total count is, of course, influenced by the ejaculate volume. The usual standard given for total counts is "over 150 million." In this series, 18 of the 100 cases had total counts below 150 million. The fact that specimens of very high volume are so often infertile leads us to believe that that total count (usually satisfactory in these cases) is not as significant as the count per unit volume. Morphology
In our preliminary report, 9 comprising a study of 40 men of repeatedly proved fertility, the only consistent finding was a relatively low percentage of abnormal sperm in all cases. In the present series of 100 cases, a somewhat wider variation of abnormal morphology was found, in that 3 of the specimens exceeded the arbitrary "20 per cent" standard, one case having 30 per cent abnormal forms. However, the average percentage of abnormal types remained relatively low ( 11.6 per cent). Good morphology still remains, therefore, a fairly consistent quality of the fertile specimen, as far as our series is concerned. Only 2 per cent of our cases had greater than 25 per cent abnormal forms. This compares rather closely to Hotchkiss' series of 200 fertile men in which 5 cases, or 2.5 per cent, had over 25 per cent abnormal forms. Weisman's 23 pregnancy group had no higher than 20 per cent abnormal cells, and Kleegman's 10 fertility series had no higher than 25 per cent. MacLeod, 16 however, in a fertility study of 874 cases, found that as many as 39 per cent of the cases had more than 20 per cent abnormal forms, and 17 per cent had over 30 per cent abnonnal types. Jeffcoate reported pregnancy in 6 cases in each of which the husband's semen exhibited more than 50 per cent abnormal forms (the exact numbers are not
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stated). And Michelson mentions 4 cases where conception took place with greater than 25 per cent abnormal types in each case. Although the above reports appear to conflict, it must be remembered that such variation in results may be explained in several ways. First, there is a difference in the number of cases studied. It may well be that if our present study could be extended much further, a higher incidence of morphologic abnormalities would be found. Secondly, there is usually a difference in interpretation of various morphologic types. Finally, different results may reflect different degrees of fertility of the groups studied. We are now in a position to discuss the question which was raised at the beginning of this paper, namely, what constitutes a normal semen? The results of this study would seem to indicate one thing clearly-that a semen cannot be classified as "normal'' or "abnormal" on the basis of any one finding. Our data show that the majority of our specimens were good, according to present standards. But enough of the specimens were "poor," according to the same standards, to warrant real doubt as to the validity of those standards. Our data also show that there were no specimens in which every aspect of the semen was "deficient," and this appears to be of significance. Many cases with low counts, for example, had good motility or morphology. A compensatory feature seemed to be present in all cases where some qualities of the semen appeared poor. The morphologies in our series were, as a group, more consistently good ·than any other phase of the analysis. This seemed to be the chief compensating feature in our group and, indeed, of similar importance in other series. Many of the reports of pregnancy occurring in the face of low sperm counts emphasize good morphology. In Weisman's 23 fertility series, all relatively low counts were accompanied by good morphologies. Hoffman reported 27 patients who were able to impregnate their wives; the counts were all below 60 million per cc., but the morphology was consistently good (12-16 per cent abnormal forms) in all these cases. In Hotchkiss'4 group of 200 fertile men, 50 had counts below 60 million per cc., yet only 5 of the 200 cases had abnormal forms exceeding 25 per cent. Just as a couple's ability to effect conception seems to depend upon the combined fertility of man and wife, so the fertilizing capacity of any given semen may depend upon the interrelationship of its various components (volume, motility, count, morphology). No one of these factors must necessarily be of top quality to achieve fertilization but, in our experience, there is at least one "good" aspect to the fertile semen which appears to make up for any deficiencies present. In this series, the best "compensating" factor was good morphology. That the men studied in our selected group were all very fertile is unquestioned. Hence one may conclude either that our present standards are correct and some fertile men have "abnormal" semen, or that fertile men have "normal" semen and that the standards accepted at present are incorrect. We prefer to accept the latter view, and to suggest that our standards of normality are too high, particularly if they are used to measure a man's ability to effect fertilization. Knowing how "deficient'' a fertile semen may appear, we do not propose any new standards, for it would not be possible to draw the line anywhere for any of the seminal
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factors. We do feel, however, that there should be at least one good quality in the normal semen, preferably, but not necessarily, good morphology.
SUMMARY AND CONCLUSIONS 1. Complete semen analysis was carried out in a group of 100 men of repeatedly proven fertility. The wives of these men were all pregnant at the time of study, now have 2 or more normal children, and have never had a spontaneous miscarriage. By means of a questionnaire, further evidence of high fertility was ascertained in 91 of the cases. 2. The age of the men appeared not to influence the results in any manner. 3. The volume of the ejaculate averaged 2.9 cc. No direct correlation was noted between the volume and the sperm count per cc. 4. No constant relationship was seen between viscosity and turbidity, and any other phase of the analysis. 5. Motility estimation revealed an average of 61.4 per cent active cells at the end of three hours. At the end of six hours the motility averaged 46.5 per cent, and at the end of twelve hours 26.5 per cent. 6. Nine specimens showed a relatively low percentage of motile forms and 8 of these exhibited poor quality of motion as well. 7. The spermatozoa count per cubic centimeter was less than 60 million in 15 of the 100 cases. Seven specimens had counts below 40 million. The average count for all cases was 100.7 million per cc. 8. The average total count was 295 million. Eighteen specimens had total counts below 150 million, and twelve of these had counts below 60 million per cc. 9. In the study of morphology, the average percentage of normal forms was 88.4 per cent. Abnormal forms ranged from 3.0 per cent to 30 per cent with an average incidence of 11.6 per cent. 10. No specimen was poor in every phase of the analysis. One-third of the cases were "deficient" in one or more aspects of the analysis, according to present standards, but all these had at least one good "compensating" feature. 11. No single aspect of the semen must necessarily be of top quality to effect fertilization, but good morphology, although not absolutely necessary for fertility, is perhaps a more stabilizing influence than any other factor of the semen.
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REFERENCES 1. Belding, D. L.: Am. J. Obst. & Gynec. 27:25, 1934. 2 ..Farris, E. J.: Anat. Record, 100: No.4, 194S. 3. Hoffman, E. F.: West. J. Surg., Obst., & Gynec. 56:155, 1948. 4. Hotchkiss, R. S., Brunner, E. K., and Grenley, P.: Am. J. M. Sc. 196:362, 1938. 5. Hotchkiss, R. S.: J. Urol. 45:875, 1941. 6. Hotchkiss, R. S.: Fertility in Men. Philadelphia, J. B. Lippincott Co., 1944. 7. Jeffcoate, T. N. A.: Brit. M. J. 2:185, 1946. 8. Keshin, J. G., and Pinck, B. D.: Am. J. Surg. 66:346, 1944. 9. Kaufman, S. A.: Human Fertility, 11:3, 1946. 10. Kleegman, Sophia J.: Am. J. Surg. 33:392, 1936. 11. Kleegman, Sophia J.: Personal Communication. 12. Lane-Roberts, C., Sharman, A., Walker, K., and Weisner, B. P.: Sterility and impaired Ferttiity. New York, Paul B. Hof'ber. lnc., l\:109. 13. MacLeod, J.: Diagnosis of Sterility. Springfield, Ill., Charles C Thomas, 1946. 14. MacLeod, J., and Hotchkiss, R. S.: Am. J. Obst. & Gynec. 52:34, 1946. 15. MacLeod, J.: Fertility and Sterility, 1:347, 1950. 16. MacLeod, J.: Fertility and Sterility, in press. 17. Meaker, S. R.: Human Sterility. Baltimore, Williams & Wilkins, 1934. 18. Meaker, S. R.: Personal Communication. 19. Michelson, L., and Michelson, R.: J. A. M.A. 134:941, 1947. 20. Moench, G. L.: Am. J. Obst. & Gynec. 25:410, 1933. 21. Moench, G. L.: Urol. & Cut. Rev. 53:406, 1949. 22. Pollak, 0. J.: Urol. & Cut. Rev. 52:592, 1948. 23. Weisman, A. I.: Urol. & Cut. Rev. 47:166, 1943. 24. Weisman, A. I.: Spermatozoa and Sterility. New York, Paul B. Hoeber, Inc., 1941. 25. Wilhelm, S. F.: Male Sterility. New York, Oxford University Press, 1937. 26. Williams, W. W., and Savage, A.: Cornell Veterinarian 15:353, 1925.
SOCIETY NEWS Registration for 1951 Atlantic City Meeting The American Society for the Study of Sterility has selected the RitzCarlton Hotel on the Boardwalk, Atlantic City, N.J., as headquarters for its Seventh Annual Convention. The sessions will be held on June 9th and lOth. It is advisable that registration for the meeting be made as soon as possible with the secretarv's office and reservations for hotel accommodations made directly with the Ritz-Carlton Hotel in Atlantic City. The preliminary program of the sessions will appear in an early issue of the JoURNAL. .I
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What Constitutes a Normal Semen? Henry C. Folk, M.D., and Sherwin A. Kaufman, M.D.
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T.m STANDARDS established for normal fertile semen vary with different observers, depending upon what each worker in the £eld regards as important. Some investigators have emphasized sperm morphology as the chief factor in evaluating a specimen. 12 • 20 Others stress the importance of the sperm count-and even here there is a difference of opinion as to whether count per unit volume or the total count is .the more important. 1 • 14 • 25 Still others feel that motility is the prime factor, and one investigator states that the total number of moving spermatozoa in the entire ejaculate is the chief index of fertility. 2 Moreover, there are varying standards for each of these separate aspects of semen analysis.
MORPHOLOGY A good deal of controversy has arisen regarding the importance of sperm morphology ever since Williams and Savage, in 1925, reported a high correlation between the breeding record of bulls and the morphology of their spermatozoa. These authors concluded that "morphology of the head of the sperm constitutes the greatest single source of information as to the £tness of the cells for reproduction." A few years later, Moench20 applied this type of study to the human, and was even more specilic in his conclusion that when the number of abnormal forms is "above 25 per cent, there is always sterility." Kleegman10 analyzed the semen of 50 men where conception took place at will and normal children were born. Only in a single case did the abnormal forms reach as high as 25 per cent. A similar series of 25 men whooe wives conceived without difficulty was studied by Weisman, 23 From the Department of Obstetrics and Gynecology, Beth Israel Hospital, N. Y. 489
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who found that the number of abnormal forms did not exceed 20 per cent in any case. And in England, Lane-Roberts et al. analyzed groups of fertile and infertile men, and stated that "no man whose reproductive record could be regarded as satisfactory produced more than 18 per cent of spermato_zoa with abnormal head forms." Somewhat different results, however, were obtained by Hotchkiss, Bruner and Grenley in a study of 200 men whose wives were pregnant and were delivered of normal children. In their series, 5 cases had 25 per cent or more abnormal forms, the highest being 32 per cent. Jeffcoate reported 6 cases of pregnancy with the husbands' sperm specimens exhibiting over 50 per cent abnormal forms in each case. MacLeod 16 is at present making a careful study of a large group of men whose wives are pregnant. Morphologic analysis of 874 of his cases revealed that as many as 39 per cent of the specimens exhibited more than 20 per cent abnormal forms; 17 per cent of the cases had more than 30 per cent abnormal forms; and 3 per cent had higher than 50 per cent abnormal sperms, the highest being 80 per cent!
NUMBER OF SPERM Equally controversial has been the question of the sperm count in sterility, particularly since Meaker, 17 in 1934, stated that in his experience "no pregnancy has occurred in cases where the sperm count was below 60,000,000." Actually, Meaker has since modified this statement to the extent of feeling that "counts considerably below 60,000,000 are not incompatible with the capacity to procreate, particularly if the morphology of the spermatozoa is good." 18 There have been a number of reports substantiating the view that fertile matings may take place in spite of definite oligospermia. In the series studied by Hotchkiss et al., 52 of the 200 fertile men had counts less than 60,000,000 per cc. In Kleegman's 10 series, however, all of whom were of very good fertility, only 1 case exhibited a count less than 60,000,000 ( 35,000,000 per cc.). MacLeod 14 obtained complete histories on 140 sterility cases in which 24 pregnancies eventually took place. Although the majority ( 60 per cent) of the husbands in the pregnancy group exhibited good semens, there was a group of 7 pregnancies in which the semen specimens were poor, inasmuch as their sperm counts averaged only 31,000,000 per cc. One of these specimens was as low as 5,000,000 per cc. with very poor motility, yet pregnancy took place. In MacLeod's 16 series, analyzing the sperm counts of
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1000 fertile men, he found that 290 of them ( 29 per cent) had counts of less than 60,000,000 per cc.; 16 per cent had less than 40,000,000 per cc.; and 2 per cent ( 20 cases) had less than 10,000,000 per cc., the lowest count being 1,000,000 sperm per cc.! The relative importance of the total count versus the count per cc. has also received considerable attention. MacLeod and Hotchkiss, in a study of 1500 cases of sterile marriage, emphasized the sperm count per unit volume rather than the total count. On the other hand, Belding felt that a low count in itself does not necessarily indicate poor fertility. He emphasized the total number of spermatozoa as a "more accurate method of expressing results than the number per cubic centimeter." The total count was also favored by Wilhelm, who felt it was a more reliable index of fertility.
MOTILITY The question of sperm motility has likewise been the source of much debate. On the one hand, Farris states that "the index of fertility in man is based on the number of moving sperm in the total ejaculate." Taking the opposing view, Moench 21 states that motility is "no criterion for the fertilizing power of a spermatozoa." He points out that some sperm may have temporary immotility, that cell collision may impart apparent motion to some cells, and that some abnormal spermatozoa may be just as motile as normal looking sperm, and may retain their motility as long or even longer. Keshin and Pinck also report that specimens containing a large percentage of abnormal forms may remain motile as long as normal spermatozoa, whereas Weisman24 holds a contrary opinion. Pollak studied the relationship between head abnormalities and motility. He found that giant heads are generally sluggish and that sperm with a displaced or absent centrosome are often immotile. On the other hand, he found that when the sperm head is smaller than normal, motility is preserved. PRESENT STUDY Because of such varying reports and lack of standards, it was felt that the question of what constitutes a "normal" semen could be answered only by a study of a very carefully selected group of cases, namely, men of unquestionable and repeatedly proven fertility. We assumed that any semen capable of producing 2 or more normal children, with no history of spontaneous miscarriage, is definitely a "normal" specimen. Our object was then
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to determine the characteristics and variations found in such carefully selected cases. A preliminary report of this study, comprising 40 selected cases, was published in 1946.9 Semen analysis was carried out on single specimens from 100 men whose wives ( 1) were pregnant at the time of study, ( 2) have now had two or more normal children, and ( 3) have never had a spontaneous miscarriage. The wives of these men were all indigent patients of the Beth Israel Hospital prenatal clinic.
..
FIFTY-TWO PLANNED PREGNANCIES
(Coitus One to Four Times per Weelc) 15
12 ~ 9 a
v
6
14
3 2
3
4-5
Months FIGURE
1.
Duration of exposure before conception.
Further evidence regarding the fertility and sex habits of these patients was obtained by means of a detailed questionnaire. Of the 91 women who have replied, 39 ( 43 per cent) termed their latest pregnancy an "accident." Since all in this group used some method of contraception (chiefly withdrawal or condom), a pregnancy as a result of an "accident" in itself indicated a high degree of fertility. The other 52 women had "planned" the pregnancy, practically all having practiced contraception previously (chiefly by use of the condom in this group). Of these 52 planned pregnancies, 15 became pregnant after one month of trial, 10 after two months, 15 after three months, 6 after four to five months, and 6 longer than five months but
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within a year (Fig. 1). That is, over. three-fourths of the women who planned their latest pregnancy conceived within three months. The frequency of intercourse in this group varied from one to four times weekly, the majority indicating twice a week. Practically all of the 91 cases in which a detailed history could be ascertained, therefore, gave further proof of good fertility. METHOD OF OBTAINING SPECIMENS
Each of the wives, in the course of regular prenatal clinic visits, was provided with a clean, dry, wide-mouthed glass bottle with a cork stopper, and given the following written instructions: The husband was to abstain from sexual relations for a minimum of three days before the date of collection. On the morning of the wife's next prenatal clinic visit, the husband was to produce a semen specimen either by masturbation into the bottle or by coitus, withdrawing just before emission and ejaculating directly into the bottle. No specimen was accepted if there was any reported loss during collection. All specimens were carried directly to the clinic by the wife in her handbag, the exact time of collection being noted on the bottle. More than half the specimens were examined within three hours of emission, the rest within four hours. METHOD OF ANALYSIS
Standard clinical procedures were used in all cases, observations being made at room temperature. Each specimen was first grossly examined to note the general appearance, amount of liquefaction, and relative turbidity. Viscosity was tested by stirring the specimen with a wooden applicator and noting the tenaciousness of the fluid upon withdrawal of the stick. The specimen was then transferred to a clean, dry, graduated glass cylinder for volume determination. Motility was studied by placing a large drop of semen on a glass slide with a cover slip, and using an ocular provided with a disc that obliterates all but one-quarter of the field. Where the number of sperm were very great, a disc with a more restricted field was used. The number of motile cells in the narrowed field was counted as rapidly as possible, and then the total number of cells in the same field was counted. The ratio of the former figure to the latter gave the percentage of motile cells. Two or three such quarterfields were thus examined, and the average taken, with the exclusion of
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extreme variations. Motility studies were done at approximately three- or four-hour intervals during the first twelve hours, and again at the end of twenty-four hours. The quality of motion was judged as good, fair, or poor, "good" being active, rapid movements across the field. The sperm count per cubic centimeter was determined, after thorough shaking of the specimen, by diluting to 1:20 in a white blood cell pipette using a diluent of 5 per cent sodium bicarbonate solution with 1 per cent formalin. All the cells in the red blood cell field of a standard Neubauer chamber were counted, giving the count per square millimeter. From this figure, the count per cubic centimeter was computed. Two separate counts were made in each case, and the average taken. The total count was obtained by multiplying the count per cc. by the volume. Morphology studies were carried out by preparing a thin smear of semen on a glass slide. A new slide was first washed in 95 per cent alcohol to remove the thin coat of oil usually present. After preparing the smear, the slide was fixed in 10 per cent formalin for two minutes, then placed into Mayer's hematoxylin for one minute, and then immersed in warm water for one minute. Morphologic types were considered largely according to the criteria of Hotchkiss et al. Seven general groups were recognized: oval (normal), small, large, tapering, round, amorphous, and double. Two hundred spermatozoa were counted and tabulated for each case. Certain disfigurements of the tail such as angulation, coiling, or complete absence of the tail were considered as possible artifacts and were purposely omitted from the count. Microprojector tracings of the various types met are shown in Figure 1 of a previous report. 9
RESULTS The results of this study are tabulated in detail in Table 1. The age of the husband varied from 25 to 54 years, the average being .:34.2 years. The volume of the ejaculate varied from 0.5 cc. to 5.2 cc. A peak volume of from .:3.0--.:3.5 cc. was reached by .:30 per cent of the cases (Fig. 2), while the mean volume for all cases was 2.85 cc. (standard deviation 0.93). Although there were 11 cases in this series with volumes less than 2.0 cc., only 1 specimen was less than 1.0 cc. ( 0.5 cc. ) . This specimen also exhibited a relatively low sperm count (50 million per cc. ) , although the motility was satisfactory. A second specimen from this man, given three months after
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WHAT CONSTITUTES A NORMAL SEMEN?
TABLE 1.
Age Volume in cc. Per cent motility ( 2-4 hr.) Per cent motility ( 6-7 hr. ) Per cent motility ( 12 hr.) Per cent motility ( 24 hr.) Sperm count" per cc. Total sperm count" Per cent abnormal forms Per cent small Per cent large Per cent tapering Per cent round Per cent amorphous Per cent double
Summary of Findings Number
Mean
100 100 100 68 71 92 100 100 100 100 100 100 100 100 100
34.2 2.85 61.0 45.9 26.5 8.0 101.0 295.0 11.6 2.3 2.4 3.0 1.6 2.1 0.3
5.5 0.93 12.3 13.5 11.8 5.9 45.0 178.1 4.5 1.2 1.4 1.4 1.0 1.9 0.5
• In millions.
30 27 24 21
18 ... 15 cu
:t:12
u
9
6 3
.
•
~~~~. g;~:i::: I I I I I I I 1 1
onollftO""'O~oono
o....:....:c-ic-iC'I'i""..r..r.n
Volume in C C FIGURE
2.
Volumes of ejaculates.
the first, showed a volume of 1.0 cc., a count of 58 million per cc., with good motility and morphology. Viscosity was abnormally high in 7 of the 100 specimens, even after many hours of standing. Two of these had a very high sperm count (over 200 million per cc. ) , 1 had a relatively low count (50 million per cc. ) , and the others had counts ranging between 90 and 135 million. All had good motility.
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Turbidity was increased in four cases. Only one of these had a relatively high sperm count ( 225 million per cc. ) . Decreased turbidity was found in 2 cases, one of which exhibited a low count ( 28 million per cc.) and poor motility. The average percentage of motile forms decreased as the time increased (Fig. 3). All specimens were examined within four hours. The motility during this interval ranged from 30 per cent in one case to 82 per cent in another, the average for all cases being 61 per cent. At the end of six to seven hours, the average percentage of motile forms for the 68 cases Cases
53
46 23
26 14
71
92
60
.
,.;- 50
·= 0
-
:e 40 c
Q>
v
; 30 A. Q>
en
f 20 Q>
>
cc 10
. .L 24
Hours after Ejaculation FIGURE
3.
Duration of motility.
examined varied from 12 per cent to 70 per cent, with an average of 45.9 per cent. After twelve hours, examination of 71 cases showed a motility range of from 2 per cent to 50 per cent with an average of 26.5 per cent. After twenty-four hours, examination of 92 cases showed a range of from 0.0 per cent to 21 per cent motile forms, with an average of 8.0 per cent. Nine cases had a relatively low percentage of active forms, with no motility at all at the end of twenty-four hours. In 6 of these specimens the sperm count was reduced as well (all below 40 million per cc.). The other 3 cases had counts of 56, 60, and 150 million per cc., respectively. Moreover,
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the quality of motility was "poor" in 8 of the 9 cases, but was consistently "good" or "fair" in all the others. The spermatozoa count per cubic centimeter varied from 28 million in one case to 225 million in another. The average count for all cases was 100.7 million per cc. In 15 of the 100 cases ( 15 per cent) the sperm count was below 60 million per cc. Eleven of these had total counts below 150 million. Moreover, the volume was found to be below 2.0 cc. in 4 of the 15 cases and the percentage of motile spermatozoa was relatively low in 7 (almost half); however, the morphology was "poor" in only 1 of these cases. Follow-up of the husband with the lowest count ( 28 million per cc.) revealed no physical abnormalities and an essentially negative history. A second specimen from this man, given six months after the first, revealed a count of 48 million per cc., a volume of 2.2 cc., and 54 per cent motile cells at the end of three hours. His wife has since been delivered of a normal child, her fourth. Total cell counts varied from a low of 25 million in one specimen with a volume of only 0.5 cc., to a high of 1 billion, 80 million in another (volume 4.8 cc.). The average total count for all cases was 295 million. The total count was below 150 million in 18 of the 100 cases. Of these, 12 cases had counts less than 60 million per cc., and 6 exhibited poor motility. Morphology study revealed an average percentage of normal (oval) forms of 88.4 per cent, with a range of from 70 to 97 per cent. The percentage of abnormal forms was relatively low, the average for all cases being 11.6 per cent. In no case did the number of abnormal forms exceed 30 per cent. Three cases had more than 20 per cent abnormal forms; 2 of these had counts below 60 million per cc., and 1 had poor motility as well. Of the abnormal types, the tapering forms occurred with greatest frequency, ranging from 0.0 per cent to 7.0 per cent with an average of 3.0 per cent for all cases. Large forms were next most frequent, with a range of from 0.0 per cent to 7.0 per cent and an average incidence of 2.4 per cent. Small forms ranged from 0.0 per cent to 6.0 per cent and averaged 2.3 per cent. Amorphous types ranged from 0.0 per cent to 14.0 per cent and averaged 2.1 per cent. Hound forms averaged 1.6 per cent. Double forms (double heads or tails) were distinctly rare. They were found in only 19 of the 100 cases, with a range of from 0.0 per cent to 2.0 per cent and an over-all incidence of only 0.3 per cent.
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DISCUSSION Age
No correlation was noted between any phase of the semen analysis and the husband's age. Volume The ejaculate volumes in this series ranged from 0.5 to 5.2 cc. The absence of very high volumes appears to be of significance, particularly when judged in the light of other reports. Kleegman, 11 for example, has never seen a fertile semen with a volume as high as 10-12 cc. Of the 200 fertile cases reported by Hotchkiss et al. there were only 2 cases with volumes as high as 9.0 cc. MacLeod15 has recently made an extensive analysis of ejaculate volumes in 800 fertile men and 600 men in infertile marriage. He found that the mean volume was 3.33 cc. for the fertile group, and 3.59 cc. for the infertile group. He feels that this difference is statistically significant, particularly since comparison with other fertility-infertility series shows a consistently higher mean volume for the infertility groups. He also found that, in general, "the highest semen volumes are associated with infertile individuals who had never produced conception and whose semen is of poor quality." It should be borne in mind, however, that in any individual case, a large volume per se does not necessarily constitute an infertile specimen. In MacLeod's fertility series comprising 1000 men, the mean ejaculate volume was 3.4 cc., but there were 48 specimens over 6.5 cc., the highest volume being 9.5 cc.! In the study of ejaculate volumes, results may vary according to whether the emission was produced by masturbation or withdrawal, there being a greater likelihood of loss during collection of withdrawal specimens. The difference between our mean volume (2.9 cc.) and that of MacLeod's series (3.4 cc.) might be explained partly by the fact that in our group most of the specimens were obtained by withdrawal rather than by masturbation. In regard to relatively low volumes, 11 per cent of the cases in our present series had less than 2.0 cc. ejaculate, but only one was less than 1.0 cc. These low-volume specimens were as good in other respects as specimens with higher volume. In an analysis of 1500 cases of sterile marriage, MacLeod and Hotchkiss found "negligibly few cases in which low volume could be considered as the source of infertility." Viscosity
The significance of increased viscosity is not clear. Hotchkiss 6 believes that a "thick ejaculate hampers the progress of the sperm by mechanical obstruction." MacLeod, 13 on the other hand, has found no real correlation between high viscosity and subnormal motility, and feels that specimens showing active motility are not likely to be hindered by high viscosity in their migration into the cervical canal. In our series, 7 cases of which showed increased viscosity, there was no correlation between the thickness of the ejaculate and poor motility or count. The chief difficulty with these specimens is drawing the semen into a pipette for counting purposes.
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Turbidity No special significance could be attributed, in this series, to either increased or decreased turbidity as an isolated characteristic.
Motility Eighty per cent of the cases had an initial motility of 50-80 per cent (Fig. 4), while the duration of motility is shown in Figure 3. The average initial motility for all cases was 61.0 per cent, examination being made within four hours. This
...
30 27 24 21
= 18 ~ IS 12 9
6 3
.
10 20 30 40 50 60 70 80 90 100 FIGURE
Per Cent Active Cells 4. Initial motility.
corresponds rather closely to the results obtained by MacLeod 16 in an analysis of 710 fertile cases; the average motility within five hours of ejaculation in his series was 58 per cent. These motility figures would seem to indicate that our present standards for initial motility are set too high, and that what may appear to be 90-95 per cent active cells at first glance will generally prove to be considerably less when careful count is made. Farris states that "an infertile male is one possessing less than 83 million moving sperm" in the entire ejaculate. This implies that any specimen with a total count of less than 83 million is infertile, even assuming 100 per cent motility. Yet in our series alone, there are 6 cases with total counts below 83 million, and all are specimens from definitely fertile individuals. However, in our series, there was a definite correlation between a lowered motility (less than 45 per cent active forms on initial examination) and other aspects of the analysis; 6 of the 9 cases with decreased motility had reduced sperm counts and almost all had poor quality of motion as well.
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Count
Perhaps the greatest source of erroneous impression in regard to the fertilizing capacity of a semen specimen is the sperm count. One even hears the term sperm "count" being used almost synonymously with sperm "analysis," as if it were the only factor to be considered. As with motility, our present standard for "normal" sperm counts appears to be too high. We have already mentioned some of the numerous reports in the literature concerning cases where pregnancy took place with relatively low counts. These should not be thought of as isolated instances. In our own group of 100 men of unquestionable fertility there were 15 specimens with counts below 60 million per cc., almost half of these being below 40 million per cc. In Hotchkiss' group of 200 fertile men, 25 per cent had counts below 60 million per cc., and in MacLeod's 16 recent study of 1000 fertile men, 29 per cent had fewer than 60 million spermatozoa per cc. Whether the difference in these figures represents degrees of relative fertility is a matter of conjecture. The main point is that our arbitrary standard of 60,000,000 is too high. We have found, however, as MacLeod has pointed out, that as the sperm count falls below 60 million per cc., other "deficiencies" begin to appear with increasing frequency. Of the 15 men in our present series whose counts were below 60 million, almost half had deficient motility, three-fourths had total counts below 150 million, and one-fourth had ejaculate volumes below 2.0 cc. The morphology was "poor" in only 1 of these cases, however. The total count is, of course, influenced by the ejaculate volume. The usual standard given for total counts is "over 150 million." In this series, 18 of the 100 cases had total counts below 150 million. The fact that specimens of very high volume are so often infertile leads us to believe that that total count (usually satisfactory in these cases) is not as significant as the count per unit volume. Morphology
In our preliminary report, 9 comprising a study of 40 men of repeatedly proved fertility, the only consistent finding was a relatively low percentage of abnormal sperm in all cases. In the present series of 100 cases, a somewhat wider variation of abnormal morphology was found, in that 3 of the specimens exceeded the arbitrary "20 per cent" standard, one case having 30 per cent abnormal forms. However, the average percentage of abnormal types remained relatively low ( 11.6 per cent). Good morphology still remains, therefore, a fairly consistent quality of the fertile specimen, as far as our series is concerned. Only 2 per cent of our cases had greater than 25 per cent abnormal forms. This compares rather closely to Hotchkiss' series of 200 fertile men in which 5 cases, or 2.5 per cent, had over 25 per cent abnormal forms. Weisman's 23 pregnancy group had no higher than 20 per cent abnormal cells, and Kleegman's 10 fertility series had no higher than 25 per cent. MacLeod, 16 however, in a fertility study of 874 cases, found that as many as 39 per cent of the cases had more than 20 per cent abnormal forms, and 17 per cent had over 30 per cent abnonnal types. Jeffcoate reported pregnancy in 6 cases in each of which the husband's semen exhibited more than 50 per cent abnormal forms (the exact numbers are not
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stated). And Michelson mentions 4 cases where conception took place with greater than 25 per cent abnormal types in each case. Although the above reports appear to conflict, it must be remembered that such variation in results may be explained in several ways. First, there is a difference in the number of cases studied. It may well be that if our present study could be extended much further, a higher incidence of morphologic abnormalities would be found. Secondly, there is usually a difference in interpretation of various morphologic types. Finally, different results may reflect different degrees of fertility of the groups studied. We are now in a position to discuss the question which was raised at the beginning of this paper, namely, what constitutes a normal semen? The results of this study would seem to indicate one thing clearly-that a semen cannot be classified as "normal'' or "abnormal" on the basis of any one finding. Our data show that the majority of our specimens were good, according to present standards. But enough of the specimens were "poor," according to the same standards, to warrant real doubt as to the validity of those standards. Our data also show that there were no specimens in which every aspect of the semen was "deficient," and this appears to be of significance. Many cases with low counts, for example, had good motility or morphology. A compensatory feature seemed to be present in all cases where some qualities of the semen appeared poor. The morphologies in our series were, as a group, more consistently good ·than any other phase of the analysis. This seemed to be the chief compensating feature in our group and, indeed, of similar importance in other series. Many of the reports of pregnancy occurring in the face of low sperm counts emphasize good morphology. In Weisman's 23 fertility series, all relatively low counts were accompanied by good morphologies. Hoffman reported 27 patients who were able to impregnate their wives; the counts were all below 60 million per cc., but the morphology was consistently good (12-16 per cent abnormal forms) in all these cases. In Hotchkiss'4 group of 200 fertile men, 50 had counts below 60 million per cc., yet only 5 of the 200 cases had abnormal forms exceeding 25 per cent. Just as a couple's ability to effect conception seems to depend upon the combined fertility of man and wife, so the fertilizing capacity of any given semen may depend upon the interrelationship of its various components (volume, motility, count, morphology). No one of these factors must necessarily be of top quality to achieve fertilization but, in our experience, there is at least one "good" aspect to the fertile semen which appears to make up for any deficiencies present. In this series, the best "compensating" factor was good morphology. That the men studied in our selected group were all very fertile is unquestioned. Hence one may conclude either that our present standards are correct and some fertile men have "abnormal" semen, or that fertile men have "normal" semen and that the standards accepted at present are incorrect. We prefer to accept the latter view, and to suggest that our standards of normality are too high, particularly if they are used to measure a man's ability to effect fertilization. Knowing how "deficient'' a fertile semen may appear, we do not propose any new standards, for it would not be possible to draw the line anywhere for any of the seminal
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[Fertility & Sterility
factors. We do feel, however, that there should be at least one good quality in the normal semen, preferably, but not necessarily, good morphology.
SUMMARY AND CONCLUSIONS 1. Complete semen analysis was carried out in a group of 100 men of repeatedly proven fertility. The wives of these men were all pregnant at the time of study, now have 2 or more normal children, and have never had a spontaneous miscarriage. By means of a questionnaire, further evidence of high fertility was ascertained in 91 of the cases. 2. The age of the men appeared not to influence the results in any manner. 3. The volume of the ejaculate averaged 2.9 cc. No direct correlation was noted between the volume and the sperm count per cc. 4. No constant relationship was seen between viscosity and turbidity, and any other phase of the analysis. 5. Motility estimation revealed an average of 61.4 per cent active cells at the end of three hours. At the end of six hours the motility averaged 46.5 per cent, and at the end of twelve hours 26.5 per cent. 6. Nine specimens showed a relatively low percentage of motile forms and 8 of these exhibited poor quality of motion as well. 7. The spermatozoa count per cubic centimeter was less than 60 million in 15 of the 100 cases. Seven specimens had counts below 40 million. The average count for all cases was 100.7 million per cc. 8. The average total count was 295 million. Eighteen specimens had total counts below 150 million, and twelve of these had counts below 60 million per cc. 9. In the study of morphology, the average percentage of normal forms was 88.4 per cent. Abnormal forms ranged from 3.0 per cent to 30 per cent with an average incidence of 11.6 per cent. 10. No specimen was poor in every phase of the analysis. One-third of the cases were "deficient" in one or more aspects of the analysis, according to present standards, but all these had at least one good "compensating" feature. 11. No single aspect of the semen must necessarily be of top quality to effect fertilization, but good morphology, although not absolutely necessary for fertility, is perhaps a more stabilizing influence than any other factor of the semen.
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WHAT CONSTITUTES A NORMAL SEMEN?
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REFERENCES 1. Belding, D. L.: Am. J. Obst. & Gynec. 27:25, 1934. 2 ..Farris, E. J.: Anat. Record, 100: No.4, 194S. 3. Hoffman, E. F.: West. J. Surg., Obst., & Gynec. 56:155, 1948. 4. Hotchkiss, R. S., Brunner, E. K., and Grenley, P.: Am. J. M. Sc. 196:362, 1938. 5. Hotchkiss, R. S.: J. Urol. 45:875, 1941. 6. Hotchkiss, R. S.: Fertility in Men. Philadelphia, J. B. Lippincott Co., 1944. 7. Jeffcoate, T. N. A.: Brit. M. J. 2:185, 1946. 8. Keshin, J. G., and Pinck, B. D.: Am. J. Surg. 66:346, 1944. 9. Kaufman, S. A.: Human Fertility, 11:3, 1946. 10. Kleegman, Sophia J.: Am. J. Surg. 33:392, 1936. 11. Kleegman, Sophia J.: Personal Communication. 12. Lane-Roberts, C., Sharman, A., Walker, K., and Weisner, B. P.: Sterility and impaired Ferttiity. New York, Paul B. Hof'ber. lnc., l\:109. 13. MacLeod, J.: Diagnosis of Sterility. Springfield, Ill., Charles C Thomas, 1946. 14. MacLeod, J., and Hotchkiss, R. S.: Am. J. Obst. & Gynec. 52:34, 1946. 15. MacLeod, J.: Fertility and Sterility, 1:347, 1950. 16. MacLeod, J.: Fertility and Sterility, in press. 17. Meaker, S. R.: Human Sterility. Baltimore, Williams & Wilkins, 1934. 18. Meaker, S. R.: Personal Communication. 19. Michelson, L., and Michelson, R.: J. A. M.A. 134:941, 1947. 20. Moench, G. L.: Am. J. Obst. & Gynec. 25:410, 1933. 21. Moench, G. L.: Urol. & Cut. Rev. 53:406, 1949. 22. Pollak, 0. J.: Urol. & Cut. Rev. 52:592, 1948. 23. Weisman, A. I.: Urol. & Cut. Rev. 47:166, 1943. 24. Weisman, A. I.: Spermatozoa and Sterility. New York, Paul B. Hoeber, Inc., 1941. 25. Wilhelm, S. F.: Male Sterility. New York, Oxford University Press, 1937. 26. Williams, W. W., and Savage, A.: Cornell Veterinarian 15:353, 1925.
SOCIETY NEWS Registration for 1951 Atlantic City Meeting The American Society for the Study of Sterility has selected the RitzCarlton Hotel on the Boardwalk, Atlantic City, N.J., as headquarters for its Seventh Annual Convention. The sessions will be held on June 9th and lOth. It is advisable that registration for the meeting be made as soon as possible with the secretarv's office and reservations for hotel accommodations made directly with the Ritz-Carlton Hotel in Atlantic City. The preliminary program of the sessions will appear in an early issue of the JoURNAL. .I