I N PREVIOUS COMMUNICATIONS, 1. 2

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1 Day of Conception in Relation to Length of Menstrual Cycle A Study of 65 Conceptions Resulting from Isolated Coitus DOUGLAS P. MURPHY, M.D., and EDITHA F. TORRANO, M.D. I N PREVIOUS COMMUNICATIONS,. 2 we presented observations which indicated that a direct relation exists between the day of ovulation and the length of the menstrual cycle. They showed, further, that conception was most likely to occur if coitus or insemination were practiced 2 days before the midcycle day. The selection of the day for the coitus or insemination, was based upon the use of the rat-ovary hyperemia test. These observations confirmed previous ones made by Farris. 4 The present observations deal with a series of women who conceived as a result of isolated coitus. The day for the coitus was not selected on the basis of a laboratory test, but was based upon the average length of the individual's menstrual cycles. MATERIALS AND METHODS A series of 65 couples who complained of infertility were the subjects in this study. Each couple was advised to have coitus 2 days before the average mid cycle day. This was to be preceded by 5 days of sexual abstinence. Each wife conceived, and her pregnancy continued to term. Average Menstrual-Cycle Length The 5 or 6 most-recent consecutive cycles were used to determine each subject's average cycle length. If the average included a fraction of a day, the fraction was handled in the following manner: If the fraction was half a day or more, the following day was assumed to represent the average. If the fraction was less than half a day, it was omitted. The average cycle length was divided by 2 in order to determine the mid cycle day. If this number contained a fraction of a day, the fraction was dropped. From the Farris Institute for Parenthood, Philadelphia, Pa. 85

2 86 MURPHY & TORRANO FERTILITY & STERILITY Procedure The couple was instructed to perform coitus 2 days before the average mid-cycle day. It was advised, further, that coitus be repeated within the next few hours. This recommendation was based upon the observation that a second ejaculation within that period of time usually results in the production of approximately 25% of the number of motile sperm released in the preceding ejaculation. 5 Ages of Women FACTORS INFLUENCING SUCCESS The ages of the women at the time of their first interview are recorded in Table. The relatively advanced reproductive age of most resulted from their periods of involuntary infertility. Duration of Infertility Duration of the period of infertility was measured from the year that the couple made an uninterrupted effort to achieve conception to the year when first seen (Table 2). In most cases, the period of infertility was measured from the time of marriage or from the time that the practice of contraception had ceased. In the remaining few instances, it was measured from the time of the last conception. TABLE. Distribution According to Age of 65 Infertile Women Studied Age (yr.) No. of women 6 2 Infej tility duration (yr.) TOTAL TABLE 2. Duration of Infertility No previ0u conception Previou.. conception 0 2 5

3 VOL. 5, No.4, 964 CONCEPTION AND CYCLE LENGTH 8 Causes of Infertility A number of obvious reasons accounted for the periods of infertility. Eleven of the 65 husbands exhibited less than 20 million motile sperm per cubic centimeter of semen (Table ). TABLE. Distribution of Husbands According to Sperm Counts Motile sperm ( millions / cc. of semen) No record No. of husbands Of the 65 women, 4 had been subjected to salpingograms before they conceived, and of the 4 exhibited unilateral tubal occlusion. In almost all instances, the couples had not known the day of ovulation in the menstrual cycle, nor did they know of the need for sexual abstinence prior to that day. RESULTS Cycle-Day of Conception Table 4 summarizes data on the relation of the cycle-day of conception to the average length of the menstrual cycle, showing the wide range in the average cycle lengths and the equally wide range in the most common cycle days of conception. These data indicate that a direct relationship exists between these two characteristics, and that the cycle day of conception occurs before the midcycle day. In those cases in which the average cycle length was 28 or 29 days, the most common cycle day of conception was Day 2, 2 days before the average mid cycle day. In those instances in which the average cycle length was shorter than 28 days, the cycle day of conception took place before cycle

4 88 MURPHY & TORRANO FERTILITY & STERILITY TABLE 4. Relation of Day of Conception to Length of Menstrual Cycle No. of 'Women conceiving Av.length of cycle A t most common A t other than most (days) cycle day* common cycle day 'l'otal 2 2 (0) 2 24 (0) (ll).26 (ll) (ll) (2) 29 2 (2) () 5 2 () 2 (4) 2 5 (4) 4 (4) 5 (5) 2 (6) 40 (9) 46 (2) TOTAL *Figure in parentheses represents day of cycle. day 2; where the average cycle length was longer than days, the cycle day of conception occurred later than Day 2. A closer examination of the data in Table 4 indicates that there is a strong tendency for the cycle day of conception to fall 2 days before the average midcycle day. This is well illustrated by the cycle days of conception where the average cycle length was 24, 26, 28, 0, 2, and 46 days. The 2 conceptions which took place on other than the most common cycle day, as might be expected, did so relatively close to the latter. Of these 2 conceptions, 20 occurred either on the day before or the day after the most common cycle day. Of these 20, 5 occurred on the day following the most common cycle day, and 5 on the day before the most common cycle day. Of the remaining conceptions, one took place 2 days before, one 2 days after, and the third days after the most common cycle day. DISCUSSION Observations in this study support those of the two preceding studies: The date of fruitful coitus is related to the length of the menstrual cycle.

5 VOL. 5, No.4, 964 CONCEPTION AND CYCLE LENGTH 89 Conception is most likely to occur if coitus is performed 2 days before the mid cycle day. The rat-ovary hyperemia test is a good method for determining the best day for fruitful coitus. It has special value for those cases in which there is considerable variation in the length of recent consecutive menstrual cycles. When the test is not available, and especially in those cases in which there is little variation in the length of the recent cycles, a considerable degree of success can be achieved by recommending coitus 2 days before the average midcycle day. S. 6 St. Philadelphia 4, Pa. REFERENCES. TORRANO, E. F., and MURPHY, D. P. Cycle day of conception by insemination or isolated coitus. Fertil. & Steril. :492, MURPHY, D. P., and TORRANO, E. F. The day of conception. A study of 48 women having 2 or more conceptions by donor insemination. Fertil. & Steril. 4:40, 96.. FARRIS, E. J. A formula for selecting the optimum time for conception. Am. J. Obst. & Gynec. 6:4, FARRIS, E. J. Human Ovulation and Fertility. Lippincott, Philadelphia, MURPHY, D. P. The effect of ejaculation upon the sperm count. ]. Ural. 88:4, 962.