Studies on ovarian function in users of the progestagen only contraceptive pill.

Abstract

The presence of ovarian cysts was determined by ultrasonography in 21 women taking progestagen-only contraceptives. These pills have fewer systemic side effects than combined pills but increased bleeding irregularities, possibly related to ovarian estrogen secretion. The 21 women and 21 controls were recruited from family planning clients at the Margaret Pyke Centre, London. Women with history of pelvic pain were excluded. The pills were levonorgestrel 30 mcg (6 women), norethisterone 350 mcg (8), and ethynodiol diacetate (7). Subjects received 3 ultrasound scans with an ALOKA SSD-720 scanner during 1 menstrual cycle. A functional ovarian cyst was defined as any fluid-filled structure 39 mm diameter that subsequently failed to rupture and form a corpus luteum. Functional cysts were seen in 8 of 21 women on the 1st scan. 15/21 failed to ovulate, and 12 of these had cysts. Among 21 matched controls only 1 cyst appeared on the first scan, which regressed during contralateral ovulation. 3 controls developed cysts and did not ovulate, or 19%, significantly lower than 71% of pill users (p.01). It is known that the combined pill reduces the incidence of cysts compared to that in diaphragm users, and cysts have been reported in bearers on norethisterone implants. This is the 1st study to follow cyst formation in progesterone-only pill users.