Ultrasound demonstration of increased frequency of functional ovarian cysts in women using progestogen-only oral contraception.

Asymptomatic volunteer women with a regular pattern of uterine bleeding and using the progestogen-only oral contraceptive pill were compared with control women who were not exposed to hormones. Pelvic ultrasound scanning at the end of the next bleeding episode after recruitment demonstrated functional cysts with maximum diameters ranging between 30 and 58 mm in eight of the 21 pill users, four of whom also had palpable ovaries, three cysts regressed during the next cycle. Of the 13 women with normal ovaries initially, four developed a new functional cyst of which two were associated with pain. Of the 12 women with cysts seven complained of pain at some time during the monitored cycle. Among 21 control women only one symptom-free (42 mm) cyst was shown on the initial postmenstrual ultrasound scan and this resolved painlessly during the scanned cycle with ovulation from the opposite ovary. Ovulation was also demonstrated in 16 of the remainder; but in none of the three control women who developed asymptomatic functional cysts (35-47 mm in size) while under observation. Since 11 of the 14 pill-users who failed to ovulate also had a functional cyst, the contraceptive efficacy may depend in part on this association. Pain symptoms may make the method less acceptable and give rise to diagnostic problems and inappropriate therapies.