Temporal relationships between ovulation and defined changes in the concentration of plasma estradiol-17β, luteinizing hormone, follicle-stimulating hormone, and progesterone: II. Histologic dating

Abstract

Histologic dating of the corpus luteum has been used to obtain information on the time intervals between ovulation and defined changes in the concentrations of 17β-estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and progesterone (P) in peripheral plasma. One hundred seventy-seven women were studied over the periovulatory period. Samples of peripheral blood were taken at recorded times, every 24 hours on Days −8 to −4 from the scheduled day of laparotomy and then every 8 hours on Days −3 to +2. The surfaces of both ovaries were photographed during the operation, and excision biopsy specimens were taken of the main components. The results in 78 cases in which ovulation had occurred before operation were suitable for statistical analysis. The mean time intervals (hours) from the defined hormonal events to ovulation, and the 95% confidence limits of the estimates are as follows: 17β-estradiol rise 96.8 (86.8 to 106.9), peak 41.5 (33.6 to 49.4); LH rise 41.0 (34.9 to 47.1), peak 18.4 (13.3 to 23.5); FSH rise 31.3 (24.9 to 37.8), peak 18.8 (12.9 to 24.8); progesterone rise 11.7 (4.9 to 18.5). The results from this approach also indicated that ovulation occurred in approximately 16% of women before the LH peak and in 3% before the LH rise, but neither phenomenon was observed. The findings are compared with previously published data1 on the same temporal relationships obtained by probit analysis, using the proportion of women who had ovulated at a given time from the hormonal event. The age range of each corpus luteum was also calculated by subtracting the observed interval from the first significant rise of plasma LH to ovulation (24 to 56 hours) from the time interval between the same hormonal event and operation. The results from this method confirmed that the morphologic changes which follow ovulation occur in an orderly sequence, but the rate will vary from woman to woman, thus making histologic dating of the corpus luteum prone to a larger error than has been reported to date. Data from 120 cases, however, showed that there was a clear relationship between the histologic dating of the mature follicle or corpus luteum and the mean concentration of estradiol and progesterone in peripheral plasma taken at the time of operation.