[Ovarian function with minidose oral contraception: the ultrasound morphology of the ovaries and endocrinology]

18 healthy oral contraceptive users aged 17-35 years participated in an 8-month study of ovarian function under pill use in 1984-85. 12 used triphasic and 5 used monophasic low dose pills and 1 used a high dose monophasic pill. The women underwent sonographic examinations of their ovaries around the 12th day of the cycle under pills. Rounded anechogenic zones in the ovarian parenchyma were interpreted to be follicular structures. The woman was requested to return in 2-7 days if a possible growing follicle was identified or in the following cycle if not. After a few cycles were studied blood samples began to be sought so that radioimmunologic tests of pituitary hormones and 2 or 3 steroids could be done. The 18 patients were studied for 28 cycles in 56 sonographic examinations. 25 usable blood samples were obtained. 2 patients had 5 ultrasound examinations in a single cycle and several had only 1 in a cycle. No intraovarian structure resembling a follicle was seen in 14 cycles. In 5 cases anechogenic formations 5-10 mm in diameter were observed around the 12th day; the 2 subsequently observed on the 17th and 21st days showed a tendency to shrink in diameter but new structures 6-8 mm in diameter appeared. In 4 cases formations 7-8 mm in diameter disappeared by the 19th to 23rd day. In 4 other cases structures observed 2-5 times per cycle remained about the same size usually 10-15 mm diameter. In 1 case a 13 mm formation observed on the 24th day gave very fine mobile echoes and had pulsatile borders indicating a vascular structure. The remaining cycle showed a 5 mm formation on the left side of on the 13th day which disappeared by the 16th day while between the 13th and 24th day on the right ovary an anechogenic formation grew from 20 to 31 mm shrinking to 27 mm on the 28th day and disappearing by the 5th day of the following cycle. Levels of luteinizing hormone (LH) above 5.36 m/UI/ml and of follicle stimulating hormone (FSH) above 3.47 m/UI/ml were taken to indicate incomplete pituitary inhibition. Of 25 samples 11 taken during 9 different cycles show FSH and 8 taken during 7 different cycles showed LH levels above these floors. The progesterone level was always at the limit of detectability. Most cycles had very low levels of estrogens but 2 slightly obese patients in 4 cycles showed higher than expected estrone levels and 1 patient had elevated levels of both estradiol and estrone. The study is open to numerous methodological criticisms among others the small sample size unsystematic study of cycles choice of ultrasound apparatus and lack of control cycles for internal reference. In no case was ovulation demonstrated. The evidence of the study suggests however that the ovaries are not entirely quiescent under low dose oral contraceptives. A larger and more systematic study should be undertaken.