MORPHOLOGICAL AND FUNCTIONAL RELATIONS OF GRAAFIAN FOLLICLE GROWTH TO OVULATION IN WOMEN USING ULTRASONIC, LAPAROSCOPIC AND BIOCHEMICAL MEASUREMENTS

Abstract

The daily growth rates of ovarian follicles were recorded ultrasonically for 5 days until ovulation in 56 spontaneously ovulating women and related to endocrine and clinical parameters. Over the 5 day period, the average diameter of the follicle destined to ovulate increased from 12-23 mm, the 2nd largest follicle from 6-12 mm, the 3rd largest follicle from 5-9 mm and the 4th largest follicle from 4-8 mm. Similar but lesser growth rates occurred in the follicles in the contralateral ovary. Ovulation occurred within 24 h of the luteinizing hormone (LH) peak, and the mean peak diameter of the ovulating follicle was 23.2 .+-. 0.3 (SEM [standard error of the mean]) mm, (range 18-29 mm) before ovulation and subsequent luteal function was judged to be normal. Follicular growth was most closely correlated with increasing peripheral blood estrogen levels. In 16 women who had a laparoscopy within 12 h of the last ultrasound and following the LH peak, the mean diameter of the largest follicle as measured by ultrasound (23.6 .+-. 0.4 mm) was similar to that measured at laparoscopy (22.8 .+-. 0.4 mm) and estimated from the follicular fluid volume aspirated (average 5.8 .+-. 0.2 ml), 22.5 mm. The follicular fluid progesterone levels were high on the day of the LH peak and blood progesterone levels had risen significantly indicating that dominant Graafian follicle luteinization had already occurred prior to ovulation. Evidently ultrasonic monitoring provides a reliable follicular growth measure and allows studies correlating morphological changes with both normal and abnormal endocrine function of the human ovary.