Ultrasound measurement of ovarian follicles stimulated by human gonadotropins for oocyte recovery and in vitro fertilization

Ultrasonic monitoring of ovarian follicles and estimation of serum estradiol (E₂) were performed in 51 patients in whom oocyte aspiration for in vitro fertilization was planned. All patients received human menopausal gonadotropin and human chorionic gonadotropin. The daily growth rates of ovarian follicles were recorded ultrasonically for 6 days prior to aspiration. Serum plasma E₂ was determined daily during the same period. Follicular dimensions based on the volume of aspirated fluid correlated very well with the ultrasonic measurements. Follicular growth was correlated with increasing peripheral blood E₂ levels. The mean follicular diameter increased from 10.8 mm 6 days before aspiration to a maximum of 16.0 mm on the day of presumptive ovulation in a group of patients characterized as low E₂ responders. In normal and high E₂ responders, the values were from 9.7 mm and 10.5 mm to 16.9 mm and 17.6 mm, respectively. The mean sizes of the follicles by ultrasound 20 hours before laparoscopy were 16.0 mm for the right ovary, 16.6 mm for the left ovary, and 18.5 mm in patients with only one ovary. At laparoscopy the mean diameters calculated from the volume of the aspirated fluids were 17.5 mm, 17.4 mm, and 19.3 mm, respectively. Multiple follicles developed in all but 2 of the 51 patients.