The Study of Induction of Ovulation with Menotropins: Analysis of Results of 1897 Treatment Cycles*

Vol. 30, No. 5, November 1978 Printed in U.S.A.

FERTILITY AND STERILITY

Copyright • 1978 The American Fertility Society

THE STUDY OF INDUCTION OF OVULATION WITH MENOTROPINS: ANALYSIS OF RESULTS OF 1897 TREATMENT CYCLES*

GABRIEL OELSNER, M.D.t DAVID M. SERR, M.D. SHLOMO MASHIACH, M.D. JOSEPH BLANKSTEIN, M.D. MITCHEL SNYDER, M.DJ BRUNO LUNENFELD, M.D.§ Department of Obstetrics and Gynecology, The Chaim Sheba Medical Center Tel Hashomer, Tel Aviv University Medical School, Tel Hashomer, Israel

Ovulation and the development of a corpus luteum with intact endocrine function is the result of a perfectly balanced interaction among hypothalamic gonadotropin-releasing hormone, pituitary gonadotropins, and ovarian response. Any disturbance in one of these endocrine glands or in the complex feedback mechanism of the closed circuit would result in anovulation. The use of menotropins is appropriate for patients lacking endogenous gonadotropins or for patients having ovaries capable of a normal response but in whom drugs capable of inducing gonadotropin secretion have failed to induce ovulation. This report is based upon computer tabulations of pooled data abstracted from 510 patients to whom 1897 treatment cycles with menotropins were administered during the last 15 years. The results of treatment are based upon detailed analyses in different groups of patients to whom the same gonadotropin preparation was administered according to a similar treatment schedule. The percentage of patients who conceived following therapy (the pregnancy rate) in group I (women with negligible endogenous estrogen activity and low gonadotropin levels) was 60.4%; in group II (women with normal gonadotropin levels and distinct endogenous estrogen activity in whom all other treatments had failed) the pregnancy rate was 21.4%. The success rates (the percentages of women who took home at least one living child) were 52.1% in group I and 14.5% in group II. Altogether, 250 children were born to 184 women who conceived following treatment. The mean numbers of treatment cycles per patient were 3.69 in group I and 3 24 in group II. Among women ofgroup I who conceived, 94.1% did so within four treatment cycles and of group II patients 952% did so within six treatment cycles. The over-all mild hyperstimulation rate was 4.26% and the severe hyperstimulation rate was 0.36%. The over-all multiple pregnancy rate was 32.5%. Fertil Steril30:538, 1978

The growing interest in the last few years of ways and means with which to stimulate ovulation in anovulatory infertile women has led to results which would have been unbelievable some 15 years ago. Clinicians are now able, thanks to a collaborative effort between endocrinologists and gynecologists, to help women who were previously doomed to remain childless. The use of gonadotropins, first extracted from

Received May 15, 1978; accepted July 10, 1978. *Supported in part by Ford Foundation Grant 67-4 70 and by the World Health Organization. tReprint requests: Gabriel Oelsner, M.D., Department of Obstetrics and Gynecology, The Chaim Sheba Medical Center Tel Hashomer, Tel Aviv University Medical School, Tel Hashomer, Israel. *Computer Center, Bar-llan University, Ramat Gan, Israel. §Institute of Endocrinology, The Chaim Sheba Medical Center Tal Hashomer, Bar-Ilan University, Ramat Gan, Israel.

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INDUCTION OF OVULATION WITH MENOTROPINS

postmortem pituitaries and later from human postmenopau sal urine, revolutionize d the treatment of infertility. Borth and associatesL 2 showed that human menopausal gonadotropin s (hMG) were effective gonadal stimulators in hypophysect omized laboratory mammals. Lunenfeld and associates 3 demonstrate d that preparations from human menopausa l urine were of satisfactory potency and had no toxic pyrogenic or local irritating side effects in man. Staemmler4 confirmed the effectiveness of hMG in conjunction with human chorionic gonadotropin s (hCG) in women by inducing ovulation as demonstrated by laparoscopy . Lunenfeld and associates 5 reported 16 years ago the first pregnancy to occur after combined hMG-hCG therapy, thus proving that ovulation can be induced with such urinary extracts. The efficacy of hMG-hCG therapy in inducing ovulation followed by pregnancy has been confirmed by Rosemberg et al., 6 • 7 Buxton and Hermann, 8 Diczfalusy et al., 9 Rabau et al., 10 and others. 11 - 17 The analysis of the results of a prospective study initiated 14 years ago in our center is the purpose of this paper. This study includes 1897 treatment cycles given to 510 patients. To our knowledge it is the largest series published from one center. MATERIALS AND METHODS

Selection of Patients The suitability of patients for gonadotropi c treatment is essentially determined by the very nature of this therapy. Being a replacemen t therapy 18 it may be effective in patients lacking endogenous gonadotrop ins but having ovaries capable of responding normally to gonadotropic stimuli. The presence of normal, sensitive ovaries is sine qua non for effective hMG-hCG therapy. For clinical purposes and for the comparison of results obtained by hMG-hCG therapy we used a simple classification 19 according to which the patients were separated into two main groups:

Group I. Group I contained women with primary or secondary amenorrhea, low levels of endogenous gonadotropin s, and lack of endogenous estrogen activity. Group II. Included in group II were patients with anovulation associated with a variety of menstrual disorders (including amenorrhea ) whose urinary or serum gonadotropin levels were within the normal range and who had evidence of endogenous estrogen activity. When this study

539

was initiated 14 years ago, serum prolactin levels had not been employed for classification of patients. Although in the past 4 years all amenorrheic patients and non-amenorr heic infertile patients have had prolactin estimations, the results of these assays were not taken into consideration in the present report.

Gonadotrop in Preparation s To provoke follicular maturation, both folliclestimulating hormone (FSH) and luteinizing hormone (LH) are required. We· used gonadotropin s extracted from human postmenopau sal urine containing 75 IU of FSH/ampule and 75 IU of LH/ ampule. To simulate an LH peak in order to provoke ovulation and corpus luteum formation, hCG containing 5,000 IU/ampule was used. Throughout the study each patient received a total dose of25,000 IU ofhCG over a period of3 to 4 days. In rare cases when specifically indicated, only 5,000 to 10,000 IU of hCG were administered. In a few cases the administrati on of this hormone was abandoned altogether in order to avoid the hyperstimula tion syndrome (see under "Monitoring of Treatment"). Treatment Scheme An individually adjusted treatment scheme 20-22 was used throughout the study. According to this scheme the amount of hMG was determined in each treatment cycle by the patient's response, thus enabling the administrati on of test dose and ovulation-ind ucing dose in each treatment cycle. hMG was administered daily until an ovarian response was elicited. The hMG dose was increased by one ampule if after 7 days of hMG administrati on no satisfactory ovarian response was obtained. The administrati on of~G was continued until preovulator y follicular growth had been attained. Ovulation was then induced by the administrati on of hCG. Assessment of Complicatio ns The main complicatio ns of gonadotropi c therapy are as follows: (1) The occurrence of the hyperstimul ation syndrome (HS). HS was classified into two degrees: mild hyperstimu lation (correspondi ng to grade 2 of the classification of the World Health Organizatio n) and severe hyperstimula tion (correspondi ng to grade 3 of the classificatio n of the World Health Organization23). Only laboratory-d iagnosed HS, i.e., estrogen levels above 150 JA,g/24-hour urine, was considered HS for the purpose of this report. (2) High

540

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OELSNER ET AL.

TABLE 1. Pregnancy Rate

incidence of multiple pregnancy. (3) High incidence of abortion.

No. of women

Monitoring of Treatment Proper and meticulous control of gonadotropic therapy is essential for obtaining satisfactory results, i.e., high pregnancy rates and low incidences ofhyperstimulation. Estimation of the ovarian response to gonadotropic administration is primarily based upon one single end-pointsteroidogenesis. During the process of follicular growth the ovary secretes increasing amounts of estrogen, while the function of the corpus luteum is reflected by secretion of both estrogen and progesterone. Throughout this study serial determinations of total urinary estrogens were used for estimation of the patient's response to gonadotropic stimulation. In some cases (particularly in patients of group I) the number of chemical determinations of urinary estrogens required for monitoring of gonadotropin therapy could be reduced and supplemented by serial estimations of the cervical score. 24 • 25 This is a simple clinical method of indirect evaluation of estrogen activity by observation of several physical characteristics of the cervical mucus. In addition to estrogen determinations patients were monitored by basal body temperature records, frequent palpation of ovaries, and plasma progesterone or urinary pregnanediol measurement for the evaluation of corpus luteum function. The results of gonadotropic therapy were assessed according to (1) pregnancy rate, i.e., the percentage of patients who conceived during therapy, and (2) success rate, i.e., the percentage of patients who took home at least one living baby. These two determinations enable a fairly objective analysis of the effectiveness of hMGhCG therapy and make it possible to compare the results obtained in different groups of patients. RESULTS

One hundred and eighty-four women became pregnant; some of them had had several treatments and conceived more than once (Table 1). The over-all pregnancy rate was 36.1%. For the purpose of calculating the pregnancy rate in Table 1, only the first pregnancy of each woman was taken into consideration, disregarding how many times she became pregnant. However, the number of children listed in Table 1 reflects the total number of children conceived. If the preg-

No. of women who Pregnancy No. of became pregnancies rate pregnant

No. of children

Group I Group II

192 318

116 68

60.4% 21.4%

193 85

191 59

Total

510

184

36.1%

278

250

nancy rate is calculated according to all of the pregnancies conceived by the 510 women then the total pregnancy rate increases to 54.5% (see Table 10). Striking differences were revealed between groups I and II. The pregnancy rate in group I was almost 3 times that obtained in group II (60.4% versus 21.4%). In group I, 191 children were born, compared with only 59 children in group II. Of 250 children born, some were twins or triplets (see "Discussion"). Tables 2 and 3 subdivide patients of groups I and II into the conventional descriptive diagnostic subgroups. It can be seen from Table 2 that the pregnancy rates in primary and secondary amenorrhea are similar (47.5% and 55.2%). However in the different subgroups exhibiting galactorrhea the pregnancy rate is higher, ranging from 71.4% to 84.6%. A similar pattern can be seen in patients of group II, where the pregnancy rate varies between 16.2% and 26% in the various cycle disturbances (Table 3). In this group also, in the presence of galactorrhea, the pregnancy rate is higher, reaching 50%. The efficacy of gonadotropic therapy is probably best evaluated by the cumulative percentage of women becoming pregnant per treatment cycle. TABLE 2. Pregnancy Rate within Group I (Amenorrhea with Negligible Estrogen Activity) No. of women

No. of women who became pregnant

Pregnancy rate

67

37

55.2

60

7

5

71.4

6

59

28

47.5

52

45

34

75.5

59

13

11

84.6

11

1

1

No. of children

%

Primary amenorrhea Primary amenorrhea and galactorrhea Secondary amenorrhea Secondary amenorrhea and galactorrhea Postpartum amenorrhea and galactorrhea (Chiari-Frommel syndrome) Sheehan's syndrome

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INDUCTION OF OVULATION WITH MENOTROPINS

TABLE 3. Pregnancy Rate within Group II (with Endogenous Estrogen Activity) No. of women

Secondary amenorrhea Secondary amenorrhea and galactorrhea Oligomenorrhe a Anovulatory cycles

No. of women who became pregnant

Pregnancy rate

TABLE 5. Success Rate No. of women

No. of women who took home at least one living baby

Success rate

Group I Group II

192 318

100 46

52.1• 14.5•

Total

510

146

28.6

No. of children

%

50

13

26

12

6

3

50

2

108 154

27 25

%

ap < 0.01. 25 16.2

30 15

The data in Table 4 show that 94.1% of patients of group I who became pregnant did so within four treatment cycles. In group II 95.2% of women who conceived did so within six treatment cycles. The real success of hMG treatment was measured by the number of women who took home at least one living baby. As a result of the higher pregnancy rate in group I and the higher abortion rate in group II, the differences in success between the two groups are even more striking: 52.1% in group I and 14.5% in group II (Table 5). The over-all pregnancy wastage rate due to abortion was 28.1%. Of the 72 abortions, 47 occurred in the first trimester and 25 in the second trimester of pregnancy (Table 6). The hyperstimul ation syndrome is usually the result of excessive amounts ofhMG administered . The incidence of mild HS was 4.26% and of severe HS 0.36% (Table 7). The high incidence of multiple pregnancy may also be due to an overdose of gonadotrop ins inducing multiple ovulation. It could be considered as an additional sign of hyperstimula tion. In our present series the multiple pregnancy rate was 32.5% (Table 8). Of 68 multiple pregnancies , 53 were twins, 11 were triplets, 3 were quadruplets (2 midtrimeste r abortions, 1 term delivery), and 1 was a sextuplet (ending as a midtrimeste r abortion). Finally, it may be of interest to compare the TABLE 4. Cumulative Percentage of Patients Who Became Pregnant before or during Any Particular Cycle

aP

541

Cycle

Group I•

Group II"

Total

1 2 3 4 5 6 7 8 9 10

47.0 74.4 86.4 94.1 98.4 100.0

36.9 53.7 73.3 86.0 93.6 95.2 96.8 98.4 98.4 100.0

43.3 67.0 81.8 91.1 96.6 98.2 98.8 99.4 99.4 100.0

< 0.01 (Kolmogorov-S mirnov test).

amount of gonadotropin s used per treatment cycle in both groups (Table 9). The mean number of ampules/cycle was significantly higher in group I (41.6) as compared with group II (18. 7). The number of ampules required for each child, however, is much higher in group II (377.0 as against 154.2 in group I) since in this group many more cycles were required to achieve each pregnancy. DISCUSSION

When results of gonadotropic therapy reported in the literature are examined, it is apparent that the pregnancy rate varies within a wide range (23.1% to 95.5%) (Table 10). In our series the overall pregnancy rate was 36.1% (Table 1), which is the mean of pregnancy rates of 60.4% and 21.4% in groups I and II, respectively. The large variation in the over-all pregnancy rates as reported in the literature may be due to several causes: The first, and probably most important, factor is the relative number of patients belonging to groups I and II in any specific center. The larger the number of patients pertaining to group I the higher the pregnancy rate will be. In order to be able to compare effectively the results of gonadotropic therapy obtained in different centers, it is of the utmost importance that a uniform classification of patients should be used. Such a classification was adopted and recommende d by the World Health Organization . 23 Second, the method of calculating the pregnancy rate may also add to the large variation of pregnancy rates. Some authors consider only the first pregnancy of each woman and some the total number of pregnancies obtained in each patient. For instance, in our series the pregnancy rate can be made to vary between 36.1% and 54.5% depending upon whether only the first pregnancy or the total number of pregnancies per patient is considered. A third factor which requires careful consideration when comparing results of gonadotropi c therapy is the number of treatment cycles actually given to each patient. In our population the mean number of treatment cycles per patient was

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OELSNER ET AL.

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TABLE 6. Abortion Rate Abortions

No. of pregnancies

No. still pregnant

1st trimester

2nd trimester

Total no.

%

Group I Group II

193 85

9 13

26 21

16 9

42 30

22.8" 41.7"

Total

278

22

47

25

72

28.1

ap <0.005.

3.69 in group I and 3.24 in group II. The same information can and probably should be analyzed in a different way, i.e., by expressing the cumulative percentage of women becoming pregnant per treatment cycle (Table 4). The data in Table 4 show that, of the patients in group I who became pregnant, 94.1% did so within four treatment cycles; of the patients in group II, 95.2% became pregnant within six treatment cycles. Thus in the evaluation of drug efficacy the percentage of women becoming pregnant must be expressed in conjunction with the number of treatment cycles, since the results of the first treatment cycle are expected to be significantly lower than the cumulative results obtained when the patients were treated for several cycles. The efficacy figures and the pregnancy rates allow each patient's over-all prognosis to be determined and explained to her; i.e., a patient in group II has a 21.4% chance of becoming pregnant; if she does become pregnant, she has a 95.2% chance of doing so within six treatment cycles. Finally, two more factors should be taken into consideration when results of gonadotropic treatment obtained in different groups of patients in different centers are compared: the gonadotropic preparations used and the treatment protocol. These factors, although oflesser importance than those mentioned above, may nevertheless influence the over-all results. Careful analysis of the 1897 cycles seems to indicate certain factors which might explain the different pregnancy rates of gonadotropic treatment in groups I and II: 1. In group I at the start of each treatment cycle the ovaries were in a quiescent state, with the

majority of follicles primordial. In group II the treatment might have started at a stage when the follicle had already started to ripen under the influence of endogenous gonadotropins. This may have interfered with the treatment regimen. Thus gonadotropic therapy was usually more predictable and easier to monitor in patients in group I and capricious, variable, and difficult to manage in group II. 2. In group I lack of ovulation was almost always the sole cause of infertility, whereas in group II additional factors (mechanical, cervical, etc.) may also have been present, aggravating the infertility problem. 3. Patients of group II were preselected in a negative sense. This group included patients not only resistant to clomiphene therapy but also women who seemingly ovulated but failed to conceive when treated with clomiphene. The present series agrees with previous reports28· 29 that there are striking differences in the dose requirement between groups I and II. The dose requirement of hMG was significantly higher in group I as compared with group II (see Table 9). This shows a wholly different "endocrine milieu" accompanying the anovulatory state in these two groups. In group I the circulating levels of gonadotropins and estrogens were low, necessitating large amounts of gonadotropins to replace the lack; it was therefore substitutional therapy. Group II, on the other hand, had normal circulating hormone levels, so that only small additional amounts of gonadotropins were required. Surprisingly, there were five patients with severe HS in group I and only two in group II. This can be explained as follows: In the beginning, 14 years ago, only group I patients were treated.

TABLE 7. Incidence of Hyperstimulation Syndrome Mild hyperstimulation

No. of cycles

No.

%

TABLE 8. Multiple Pregnancy Rate

Severe hyperstimulation

No.

%

Group I Group II

158 51

60 8

38.0" 15.7"

Total

209

68

32.5

708 1189

33 48

4.46" 4.03"

5 2

0.70 0.16

Total

1897

81

4.26

7

0.36

=

0.2.

Multiple pregnancy

%

Group I Group II

ap

No. of pregnancies for which no. of fetuses is known

No.

ap <0.005.

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INDUCTION OF OVULATION WITH MENOTROPINS

TABLE 9. Ampuletl' per Cycle and per Child No. of women

Treatment cycles

Ampules/ cycle

No. of children

Ampules/ child

Group I Group II

192 318

708 1189

41.6 18.7

191 59

154.2 377.0

Total

510

1897

27.2

250

206.8

aQne ampule ofPergonal = 75 IU ofFSH + 75 IU ofLH.

Patients of group II were latecomers to treatment, when the procedure and technical knowledge of the staff had already been well established. The unpredictab ility of group II patients had been noted and taken into account. Hence, monitoring was more strict and careful. Occasionall y, the ovulatory dose ofhCG was not even given in order to avoid hyperstimul ation. In our material comprising 278 pregnancies the multiple pregnancy rate was 32.5%. Although this rate is high compared with the rate of spontaneous pregnancies, the real problem is much smaller as the vast majority of multiple pregnancies involves twin births. For the couple treated for several years for primary infertility, the birth of twins is considered a blessing rather than feared as a complication . On the other hand, the delivery of three or more children presents serious obstetric complication s and may result in social and psychologic problems. It is of interest to note that the abortion rate was higher in group II than in group I (41.7% and 22.8%, respectively ). This is a rather puzzling finding. One would expect that in women who were amenorrhoei c and had lacked endogenous estrogen for years (group 1), pregnancy induced by treatment might be more endangered than in patients who had not endured prolonged estrogen deficiency and its consequence s (group II). The reason for the higher abortion rate in group II cannot be explained. Theoretically , several causes

543

for the high abortion rate in gonadotropi ninduced pregnancies are conceivable. It is possible that exogenous stimulation of the ovaries may sometimes result in a faulty ovum ill-prepared for fertilization. Another reason for the high incidence of abortions may be the relative hyperestrogenism quite common in induced ovulations. The high estrogen levels could cause an abnormally high tubal motility resulting in an accelerated passage of the fertilized ovum and its premature arrival in a uterine cavity not yet ready for implantation . It is also quite possible that some of the ovulations induced by gonadotropin s are followed by insufficient corpus luteum formation incapable of supporting early pregnancy. This situation has been described in patients with hyperprolactinemia.30 The last important cause of fetal loss following gonadotropin -induced pregnancy is the high incidence of multiple pregnancy. It is well known that in the human, fetal wastage is significantly higher in multiple pregnancies as compared with that in single pregnancies, the main reason for the difference being the higher incidence of immature and. premature births associated with the former group. The introductio n of powerful ovulationinducing agents such as gonadotropin s has made an important contributio n to the temporary elimination of the anovulation syndrome. In spite of the risks of less than 1% severe HS, a 32.5% multiple pregnancy rate, and a 28.1% abortion rate, gonadotropic therapy is a most efficient tool in the treatment of infertility due to anovulation. When properly selected and monitored, 60.4% of patients in group I will conceive and 52.1% will take home at least one living baby. Acknowledgmen t. The skillful technical assistance with the estrogen determination s by D. Tikotzky was greatly appreciated.

TABLE 10. Results of Gonadotropin Therapy Author

Bettendorf and Insler" Brown et al. 13 Butler12 Taymor.•• Ellis and Williamson•• Lunenfeld et al. 27 Spadoni et al. 16 Thompson and Hansen14 Authors' series Total

No. of patients

No. of cycles

No. of Pregnancy pregnancies rates %

157

275

47

29.9

45 134 101 77

222 438 343 322

43 31 62 43

95.5 23.1 61.4 55.8

228 62 1190

463 225 2798

101 26 334

44.3 41.9 28.1

510

1897

278

54.5

2504

6983

965

38.5

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5. Lunenfeld B, Sulimovici S, Rabau E, Eshkol A: L'induction del !'ovulation dans les amenorrhoea hypophysaires par un traitement combaine de gonadotropines urinaires menopausiques et de gonadotropines chorioniques. C R Soc Fr Gynecol 35:346, 1962 6. Rosemberg E, Coleman J, Demany M, Garcia CR: Clinical effect of human urinary postmenopausal gonadotropins. J Clin Endocrinol Metab 23:181, 1963 7. Rosemberg E, Maher RE, Stern A, Demany M: Clinical effect of gonadotropins of human origin ..J Clin Endocrinol Metab 24:105, 1964 8. Buxton IC, Hermann W: Induction of ovulation in the human with human gonadotropins. Am J Obstet Gynecol 81:584, 1961 9. Diczfalusy E, Johannisson E, Tillinger KG, BettendorfG: Comparison of the clinical and steroid metabolic effect of human pituitary and urinary gonadotropins in amenorrhoeic women. Acta Endocrinol [Suppl] (Kbh) 90:35, 1964 10. Rabau E, David A, Serr DM, Mashiach S, Lunenfeld B: Human menopausal gonadotropins for anovulation and sterility. Am J Obstet Gynecol 98:92, 1967 11. Insler V: Cooperative study on the results of gonadotropic therapy. In Clinical Application of Human Gonadotropins. Edited by G Bettendorf, V lnsler. Stuttgart, Georg Thieme Verlag, 1970, p 1 12. Butler JK: Oestrone response patterns and clinical results following various Pergonal dosage schedules. In Development in the Pharmacology and Clinical Uses of Human Gonadotropins, Edited by JK Butler. GD Searle and Co Ltd, High Wycombe, England, 1970, p 42 13. Brown JB, Evans JH, Adey FD, Taft HP, Townsend L: Factors involved in the induction of fertile ovulation with human gonadotropins.·J Obstet Gynaecol Br Commw 76:289, 1969 14. Thompson CR, Hansen LM: Pergonal (menotropins): a summary of clinical experience in the induction of ovulation and pregnancy. Fertil Steril 21:844, 1970. 15. Ellis JD, Williamson JG: Factors influencing the pregnancy and complication rates with human menopausal gonadotropin therapy. Br J Obstet Gynaecol 82:52, 1975 16. Spadoni LR, Cox DW, Smith DC: Use of human menopausal gonadotropin for the induction of ovulation. Am J Obstet Gynecol 120:968, 1974 17. Gemzell C: Induction of ovulation in patients fallowing removal of pituitary adenoma. Am J Obstet Gynecol 117:955, 1973

November 1978 · 18. Lunenfeld B, Insler V: Classification of amenorrhoeic states and their treatment by ovulation induction. Clin Endocrinol 3:223, 1974 19. Insler V, Melmed H, Mashiach S, Monseliese M, Lunenfeld B, Rabau E: Functional classification of patients selected for gonadotropin therapy. Obstet Gynecol32:620, 1968 20. Lunenfeld B, Insler V, Rabau E: Die Prinzipien der Gonadotropin Therapie. Acta Endocrinol [Suppl] (Kbh) 148:52, 1970 21. Rabau E, Serr DM, Mashiach S, lnsler V, Salomy M, Lunenfeld B: Current concepts in the treatment of anovulation. Br Med J 4:446, 1967 22. Bettendorf G, Breckwoldt M, Neale C: Erfahrungen mit human hypophysarean gonadotropinen. Acta Endocrinol [Suppl148] (Kbh) 64:102, 1970 23. World Health Organization. Tech Rep Ser 514, 1973 24 .. Insler V, Melmed H, Rabau E, Serr DM, Lunenfeld B: Comparison of various methods used in monitoring of gonadotropic therapy. In Clinical Application of Human Gonadotropins, Edited by G Bettendorf, V Insler. Stuttgart, Georg Thieme Verlag, 1970, p 87 25. Insler V, Melmed H, Eichenbrenner I, Serr DM, Lunenfeld B: The cervical score-a simple semiquantitative method for monitoring of the menstrual cycle. lnt J Gynaecol Obstet 10:223, 1972 26. Taymor ML: Clinical applications of gonadotropin therapy in females. In Recent Research on Gonadotropic Hormones, Edited by ET Bell, JA Loraine. Edinburgh, Livingstone, 1967, p 265 27. Lunenfeld B, Insler V, Rabau E: Induction de !'ovulation par les gonadotropines. In L'Ovulation Meiose et Ouverture Folliculaire Traitements de !'Anovulation. Paris, Masson et Cie, 1969, p 291 28. Caspi E, LevinS, Bukovsky J, Weinraub Z: Induction of pregnancy with human gonadotropins after clomiphene failure in menstruating ovulatory infertile patients. lsr J Med Sci 10:249, 1974 29. Gemzell C: Treatment of female and male sterility with human gonadotropins. Acta Obstet Gynecol Scand [Suppl] 48:1, 1969 30. DelPozo E, Wyss H, Lancranjan I, Obllensky W, Varga L: Ovulation in the Human, Edited by PG Crosignani. New York, Academic Press, 1976, p 297