[Assessment of follicular development and ovulation by ultrasound]

The relation between ultrasonographic signs of ovulation and serum estradiol (E2) rise and luteinizing hormone (LH) surge were studied. Forty-eight cycles were examined in Twenty-eight infertile patients. The correlation between the follicular diameter as measured by ultrasound and actual follicular diameter under direct visualization was also determined in 19 follicles of the 25 patients who had undergone laparotomy. In 34 of the 48 cycles, growing follicles and follicular rupture could be observed by ultrasound (72.3%). The mean diameter of the follicles measured the day before estimated ovulation was 22.4 +/- 2.75 mm(range 16-27mm). The ultrasonographic ovulation period (UOP) occurred within 24 hours from the day of maximal LH levels in 24 of the 34 cycles, and within 48 hours from the day of the E2 peak in 25 of the 34 cycles. The follicular diameter measured by ultrasound was greater than the actual diameter found during laparotomy, but there was a high degree of correlation (r = 0.900). Furthermore, the E2 and P levels in follicular fluid were high in large follicles and correlated well with the ultrasound assessments of follicular size. These results suggested that ultrasonic monitoring provides a reliable measure of follicular growth and prediction of ovulation, and offers a highly sophisticated scientific tool for the study of reproductive endocrinology.