Objective: To investigate the occurrence rate of adnexal lesions in premenopausal women.
Methods: A random sample of women 25-40 years old was invited to undergo a transvaginal ultrasound examination, and 335 women were examined. The criteria used to define an adnexal lesion were either a cystic lesion with its largest diameter of at least 25 mm within the pelvic region, or the appearance of solid parts in any lesion regardless of size.
Results: Adnexal lesions were found in 26/335 cases, (7.8%) (95% confidence interval (CI), +/- 2.9%). The occurrence rate of ovarian cysts was 22/335 (6.6%) (95% CI, +/- 2.7%). There were no differences between the women with or without ovarian cysts related to age, smoking habits, parity or body mass index. At follow-up 3 months later, 18 of the 22 (82%) cysts had disappeared (95% CI, +/- 16%). Women using progesterone contraception (either oral contraception or an intrauterine device with levonorgestrel) had a significantly higher relative risk of 2.7 (95% CI, 1.1-6.9) of functional cysts as compared to women with natural cycles. Polycystic ovaries were found in 10.2% (95% CI, +/- 4.2%) of the women not using any hormonal contraception. The mean volumes of the polycystic ovaries were significantly larger compared to those in natural cycles.
Conclusion: Adnexal lesions are common in asymptomatic women in the age group 25-40 years, but four out of five ovarian cysts disappeared spontaneously after 3 months. The ultrasound appearance of the cyst, the woman's family history and her own feelings must be considered if a persisting cyst is to be surgically removed or followed by repeated transvaginal ultrasound.