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A formula for selecting the optimum time for conception
A FORMULA
FOR SELECTING THE OPTIMUM CONCEPTION* J.
EDMOND
(From
The
FARRIS,
Wtitar
PH.D.,
Institute
of
and
FOR
PA.
PHILADELPHIA,
Anatomy
TIMX
Biology)
M
ANY methods have been employed for determining the occurrence of human ovulation. These include the use of alterations in body temperature, changes in the cervical mucus, variations in the character of cells secured from vaginal smears, tissue from endometrial biopsies, increase in walking, electrometric determinations, and hormonal assays. All have their disadvantages, and none is very accurate. Recently, the rat ovarian hyperemia test has become available (Farrisl), and offers perhaps the most accurate method. The present report deals with the use of this test in the timing of the ovulation of 148 women who conceived 150 times. The results permit the development of a formula for determining the optimum time for coitus or insemination for conception. Materials and Methods
Observations were made upon three series of women. The first group of 50 women each supplied a record of the lengths of 12 or more consecutive cycles. A second series of 48 women had a total of 50 conceptions, each resulting from insemination performed only once in the month. A third series of 100 women each conceived once by coitus practiced only once during the fertile period. The time selected for either the insemination or coitus was determined by the use of the rat hyperemia test described previously.l-Q The data for series 2 and 3 are combined on account of similarity in the results. Ovulation of each patient was timed for two consecutive months. The first month’s timing was utilized as a control, and no attempt at conception was This control month test indicates the presence or made during that month. absence of normal ovulation activity, and approximately when in the month it takes place. Intercourse was advised, or artificial insemination was performed during the second month, if a normal ovulation reaction was recorded. No attempt at conception was planned if the reaction was abnormal, since conception has proved to be unlikely under such circumstances.1p 7, 8 Results The Average Length of the Menstrual Cycle.-The average length of 12 consecutive cycles of each of 50 patients was computed for 3, 6, 9, and 12 month periods. Each average was expressed in whole days. If the average included a fraction of 0.5 or more days, a full day was added to the average. Any fraction less than 0.5 of a day was omitted from the average. The average length of any 3 consecutive cycles was about the same length as the cumulative averages of that person for 6, 9, or 12 cycles. The maximum variation in the average of 3, 6, 9, or 12 cycles was not over 2 days in the majority of instances. *This
investigation
was
aided
by
a grant
from 1143
the
Samuel
S. Fels
Fund.
FARRIS
Eighteen per cent of the 50 women varied less than a ciay in the average length of 3, 6, 9, or 12 cycles. Fifty-two per cmt varied 1 da.y, and 14 pej* cat varied 2 days. The ma,jority. or 84 per crni. varied no more than 2 days. The data indicat,e that the average lengt,h of any 3 consecutive c~yclrs (expressed to t,he nearest whole day) varies so slightly from t,he average of more than 3 cycles, that only 3 consecutive cycles need bc utilized to obtain a prar*tical average. Day for Nuccessfd Insemimtion or Cl,oiWs.-Table I reveals the days ut successful insemination or coitus for the 148 women who conceived 150 times (series 2 and 3 combined). The selected day was determined by the use of tht rat hyperemia t,est . The greatest number of conceptions occurred when insemination or coitus was performed 2 days prior to the midcyclc day. For example, in Table I, in the case of the 26 day cycle, 10 of the 27 conceptions occurred when insemination or coitus took place on day 11, which was IWO days before t,he midcycle day. The next, largest number (six conceptions) took place when coitus or insemination was practiced one day before the midcycle day. The midcyelc day itself was the third most successful day (5 conceptions). This is a total of 21 of the 27 conceptions. or 78 per cent, which took pla.ce during these three days.
AVERAGE LENGTH OF3 CONSECUTIVE CYCLES" --DAYS 23 24
., 7
25 26 27 28
:,
I1
:,i;
2'7
2
“
1
2
9 7
10
0
3
1
2
2
35 38 40 41 .--__.---~. l'otal
__ of to
150
1
I
::
1
(i 2 4
34
The days hyperernia test. *Calculated
'0
R 2
1 2 2
1
; 1
1 1 1 1 ---~...__-..~-~~~
the
above
successful
the
nearest
whole
2
I
1 1 ~~ coitus
or
.-.~~~.. - ~--~
insemirtation
were
1 _-.-1 selected
---
by
the
rat
day.
Two conceptions occurred when insemination or coitus was practiced 3 days prior to the rnidcycle day, and one on the day after the midcycle day. An analysis of the remaining cycles shown in Table I reveals an equally high incidence of conceptions on the above-mentioned days. These observations suggest three schedules for selecting the optimum time for insemination or coitus. The use of these schedules should always be preceded by 5 days’ abstinence, so t,hat the husbands will possess the maximum number of active sperm cells.$
Volume 63 Number
5
SELECTING
OPTIMUM
TIME
FOR
CONCEPTION
1145
The Formula Schedule A.1. Average three recent, consecutive menstrual cycles, to the nearest whole day. A day is added if the fraction is greater than 0.5 of a day. 2. Divide this number by 2. Omit any fraction of a day. 3. Starting 2 &ys before this midcycle day, practice coitus once daily for 3 consecutive days. Schedule B.If conception fails after following Schedule A for four months: Practice coitus, starting 3 Clays before the midcycle day, daily for 3 consecutive days. Schedule C.If conception fails after following Schedules A and B for four months each : Practice coitus, starting 2 day before the midcycle day, daily for 3 consecutive days. There were 150 conceptions by timing ovulation with the rat hyperemia test (Table I). Of this number, by using Schedule A, 98 conceptions occurred as follows: 42 two days previous to the midcpcle day; 30 one day before the midcycle day; and 26 on the midcycle day. These represent 65 per cent of the conceptions. If coitus or insemination had been practiced by the women listed in Table I according to Schedule B rather than Schedule A, the first attempt 3 days previous to the midcycle day would account for 22 conceptions, with 42 and 30 more occurring on the next two days, for a total of 94 conceptions, or 63 per cent. Finally, if coitus or insemination had been practiced by the women listed in Table I according to Schedule C, with the first attempt being made one day previous to the midcycle day, 30 conceptions would have occurred, with 26 and .13 more on the next two additional days, for a total of 69 conceptions, or 46 per cent. Theoretically, then, if each of the 148 women had followed Schedules A, B, and C until they became pregnant, 89 per cent of them would have conceived by following the formula. According to the observations in Table I, the largest number would have conceived during the first four months (Schedule A). Comment After comparison of the results of other methods with those of the formula for selecting the optimum time for conception, the conclusion is reached that, with the exception of the rat hyperemia test, which is the most precise for selecting the time of ovulation, there is no method at the present time that is as satisfactory. Although the number of cases upon which this report is based is admittedly small, the results would seem to substantiate the above statement. The rat hyperemia test has revealed facts that are of value in the practical application of the formula. Ovulation occurs, generally, once every month, particularly in women at the optimum age for reproduction. The average fertile woman ovulates normally about 85 per cent of the time, or in 7 out of 8 cycles.3 In the cases in which ovulation was studied for several consecutive months in the same individual, 93 per cent of the women showed a variation in the time of occurrence of ovulation of less than 3 days, while 80 per cent
1146
FARRIS
Am. J. Obst. & Gynec May, 1952
exhibited a variation of less than 2 days. The fact Ihat ovulation occurs on nearly the same day in consecutive cycles indicates t,he necessity of performing coitus on consecutive days. It is advisable to practice one schedule for coitus or insemination for at least 4 cycles before t,he next schedu!e is used. During this first period of foul months a woman with a fertility problem is likely to exhibit 2 out of 4 normai ovulation reactions. In the absence of a normal ovulation reaction, pregnant!’ is unlikely.
Summary d method is described for select,ing the optimum t.ime for coitus or iusemination for conception. The procedure is as follows: 1. Use 3 consecutive menstrual cycles to secure an adequate average of the length. 2. Inseminate or recommend coitus, I’ollowin, 0 5 days ’ abstinence, for 3 consecutive days beginning 2 days before the midcycle day. 3. If conception fails after followinh 0‘ the above schedule for 4 months. inseminate or advise coitus, following 5 days’ abstinence, for 3 consecutive days starting on the third da!: previous to the midcycle day. 4. If conception fails following the use of t,he two above schedules, inseminate or advise coitus daily, following .5 days’ abstinence. for 3 consecl1tive days starting 1 day before the midcycle day.
References 1. 2. ::. 4. 5.
Farris, Farris, Farris, Farris, Farris,
E. J.: AM. J. OBS’~. & GYNEC. 52: 14, 1946. E. J.: Anat. Rec. 95: 337, 7946. E. J.: AK J. OBST. & GYNEC. 56: 347, 1947. E. J.: J. A. M. A. 138: 560, 1948. E. J.. Lewis, W. H., Bachman, C., and Muckle, C. W.: Anat. Rec. 100: 766, 1946 (Abst.). 6. Farris, E. J. : Human Fertility and Problems of the Male, Palisades Pitrk, N. J., 1950, The Author’s Press. 7. Murphy, D. P., and Farris, E. J.: Ax. J. OBST. & GYNEC. 54: 467, 1947. 8. Murphy, D. P., and Farris, E. J.: J. A. M. A. 138: 13. 1948. 9. Corner, G. W., Farris, E. J., and Corner, G. W., Jr.: Bar. .T. OBST. & GYNEC. 59: 514, 1950.
FOR SELECTING THE OPTIMUM CONCEPTION* J.
EDMOND
(From
The
FARRIS,
Wtitar
PH.D.,
Institute
of
and
FOR
PA.
PHILADELPHIA,
Anatomy
TIMX
Biology)
M
ANY methods have been employed for determining the occurrence of human ovulation. These include the use of alterations in body temperature, changes in the cervical mucus, variations in the character of cells secured from vaginal smears, tissue from endometrial biopsies, increase in walking, electrometric determinations, and hormonal assays. All have their disadvantages, and none is very accurate. Recently, the rat ovarian hyperemia test has become available (Farrisl), and offers perhaps the most accurate method. The present report deals with the use of this test in the timing of the ovulation of 148 women who conceived 150 times. The results permit the development of a formula for determining the optimum time for coitus or insemination for conception. Materials and Methods
Observations were made upon three series of women. The first group of 50 women each supplied a record of the lengths of 12 or more consecutive cycles. A second series of 48 women had a total of 50 conceptions, each resulting from insemination performed only once in the month. A third series of 100 women each conceived once by coitus practiced only once during the fertile period. The time selected for either the insemination or coitus was determined by the use of the rat hyperemia test described previously.l-Q The data for series 2 and 3 are combined on account of similarity in the results. Ovulation of each patient was timed for two consecutive months. The first month’s timing was utilized as a control, and no attempt at conception was This control month test indicates the presence or made during that month. absence of normal ovulation activity, and approximately when in the month it takes place. Intercourse was advised, or artificial insemination was performed during the second month, if a normal ovulation reaction was recorded. No attempt at conception was planned if the reaction was abnormal, since conception has proved to be unlikely under such circumstances.1p 7, 8 Results The Average Length of the Menstrual Cycle.-The average length of 12 consecutive cycles of each of 50 patients was computed for 3, 6, 9, and 12 month periods. Each average was expressed in whole days. If the average included a fraction of 0.5 or more days, a full day was added to the average. Any fraction less than 0.5 of a day was omitted from the average. The average length of any 3 consecutive cycles was about the same length as the cumulative averages of that person for 6, 9, or 12 cycles. The maximum variation in the average of 3, 6, 9, or 12 cycles was not over 2 days in the majority of instances. *This
investigation
was
aided
by
a grant
from 1143
the
Samuel
S. Fels
Fund.
FARRIS
Eighteen per cent of the 50 women varied less than a ciay in the average length of 3, 6, 9, or 12 cycles. Fifty-two per cmt varied 1 da.y, and 14 pej* cat varied 2 days. The ma,jority. or 84 per crni. varied no more than 2 days. The data indicat,e that the average lengt,h of any 3 consecutive c~yclrs (expressed to t,he nearest whole day) varies so slightly from t,he average of more than 3 cycles, that only 3 consecutive cycles need bc utilized to obtain a prar*tical average. Day for Nuccessfd Insemimtion or Cl,oiWs.-Table I reveals the days ut successful insemination or coitus for the 148 women who conceived 150 times (series 2 and 3 combined). The selected day was determined by the use of tht rat hyperemia t,est . The greatest number of conceptions occurred when insemination or coitus was performed 2 days prior to the midcyclc day. For example, in Table I, in the case of the 26 day cycle, 10 of the 27 conceptions occurred when insemination or coitus took place on day 11, which was IWO days before t,he midcycle day. The next, largest number (six conceptions) took place when coitus or insemination was practiced one day before the midcycle day. The midcyelc day itself was the third most successful day (5 conceptions). This is a total of 21 of the 27 conceptions. or 78 per cent, which took pla.ce during these three days.
AVERAGE LENGTH OF3 CONSECUTIVE CYCLES" --DAYS 23 24
., 7
25 26 27 28
:,
I1
:,i;
2'7
2
“
1
2
9 7
10
0
3
1
2
2
35 38 40 41 .--__.---~. l'otal
__ of to
150
1
I
::
1
(i 2 4
34
The days hyperernia test. *Calculated
'0
R 2
1 2 2
1
; 1
1 1 1 1 ---~...__-..~-~~~
the
above
successful
the
nearest
whole
2
I
1 1 ~~ coitus
or
.-.~~~.. - ~--~
insemirtation
were
1 _-.-1 selected
---
by
the
rat
day.
Two conceptions occurred when insemination or coitus was practiced 3 days prior to the rnidcycle day, and one on the day after the midcycle day. An analysis of the remaining cycles shown in Table I reveals an equally high incidence of conceptions on the above-mentioned days. These observations suggest three schedules for selecting the optimum time for insemination or coitus. The use of these schedules should always be preceded by 5 days’ abstinence, so t,hat the husbands will possess the maximum number of active sperm cells.$
Volume 63 Number
5
SELECTING
OPTIMUM
TIME
FOR
CONCEPTION
1145
The Formula Schedule A.1. Average three recent, consecutive menstrual cycles, to the nearest whole day. A day is added if the fraction is greater than 0.5 of a day. 2. Divide this number by 2. Omit any fraction of a day. 3. Starting 2 &ys before this midcycle day, practice coitus once daily for 3 consecutive days. Schedule B.If conception fails after following Schedule A for four months: Practice coitus, starting 3 Clays before the midcycle day, daily for 3 consecutive days. Schedule C.If conception fails after following Schedules A and B for four months each : Practice coitus, starting 2 day before the midcycle day, daily for 3 consecutive days. There were 150 conceptions by timing ovulation with the rat hyperemia test (Table I). Of this number, by using Schedule A, 98 conceptions occurred as follows: 42 two days previous to the midcpcle day; 30 one day before the midcycle day; and 26 on the midcycle day. These represent 65 per cent of the conceptions. If coitus or insemination had been practiced by the women listed in Table I according to Schedule B rather than Schedule A, the first attempt 3 days previous to the midcycle day would account for 22 conceptions, with 42 and 30 more occurring on the next two days, for a total of 94 conceptions, or 63 per cent. Finally, if coitus or insemination had been practiced by the women listed in Table I according to Schedule C, with the first attempt being made one day previous to the midcycle day, 30 conceptions would have occurred, with 26 and .13 more on the next two additional days, for a total of 69 conceptions, or 46 per cent. Theoretically, then, if each of the 148 women had followed Schedules A, B, and C until they became pregnant, 89 per cent of them would have conceived by following the formula. According to the observations in Table I, the largest number would have conceived during the first four months (Schedule A). Comment After comparison of the results of other methods with those of the formula for selecting the optimum time for conception, the conclusion is reached that, with the exception of the rat hyperemia test, which is the most precise for selecting the time of ovulation, there is no method at the present time that is as satisfactory. Although the number of cases upon which this report is based is admittedly small, the results would seem to substantiate the above statement. The rat hyperemia test has revealed facts that are of value in the practical application of the formula. Ovulation occurs, generally, once every month, particularly in women at the optimum age for reproduction. The average fertile woman ovulates normally about 85 per cent of the time, or in 7 out of 8 cycles.3 In the cases in which ovulation was studied for several consecutive months in the same individual, 93 per cent of the women showed a variation in the time of occurrence of ovulation of less than 3 days, while 80 per cent
1146
FARRIS
Am. J. Obst. & Gynec May, 1952
exhibited a variation of less than 2 days. The fact Ihat ovulation occurs on nearly the same day in consecutive cycles indicates t,he necessity of performing coitus on consecutive days. It is advisable to practice one schedule for coitus or insemination for at least 4 cycles before t,he next schedu!e is used. During this first period of foul months a woman with a fertility problem is likely to exhibit 2 out of 4 normai ovulation reactions. In the absence of a normal ovulation reaction, pregnant!’ is unlikely.
Summary d method is described for select,ing the optimum t.ime for coitus or iusemination for conception. The procedure is as follows: 1. Use 3 consecutive menstrual cycles to secure an adequate average of the length. 2. Inseminate or recommend coitus, I’ollowin, 0 5 days ’ abstinence, for 3 consecutive days beginning 2 days before the midcycle day. 3. If conception fails after followinh 0‘ the above schedule for 4 months. inseminate or advise coitus, following 5 days’ abstinence, for 3 consecutive days starting on the third da!: previous to the midcycle day. 4. If conception fails following the use of t,he two above schedules, inseminate or advise coitus daily, following .5 days’ abstinence. for 3 consecl1tive days starting 1 day before the midcycle day.
References 1. 2. ::. 4. 5.
Farris, Farris, Farris, Farris, Farris,
E. J.: AM. J. OBS’~. & GYNEC. 52: 14, 1946. E. J.: Anat. Rec. 95: 337, 7946. E. J.: AK J. OBST. & GYNEC. 56: 347, 1947. E. J.: J. A. M. A. 138: 560, 1948. E. J.. Lewis, W. H., Bachman, C., and Muckle, C. W.: Anat. Rec. 100: 766, 1946 (Abst.). 6. Farris, E. J. : Human Fertility and Problems of the Male, Palisades Pitrk, N. J., 1950, The Author’s Press. 7. Murphy, D. P., and Farris, E. J.: Ax. J. OBST. & GYNEC. 54: 467, 1947. 8. Murphy, D. P., and Farris, E. J.: J. A. M. A. 138: 13. 1948. 9. Corner, G. W., Farris, E. J., and Corner, G. W., Jr.: Bar. .T. OBST. & GYNEC. 59: 514, 1950.