Objective: To assess whether low-dose oral contraceptive (OC) use affects uterine size or menstrual flow in women with leiomyomas.
Methods: Eighty-seven premenopausal women with leiomyomas were enrolled in a 1-year study. Fifty-five women took low-dose monophasic OCs, and 32 took no OCs or other hormonally active medications. Uterine size was assessed by bimanual and sonographic examinations before and after the study. Duration of menstrual flow and hematocrit were also assessed.
Results: Fifty (91%) of 55 women completed 1 year of OC use. There was no significant difference in mean uterine size determined by bimanual examination or in uterine volume measured by sonography after 12 months of OC use. Likewise, there were no significant changes in these indices among the 32 women who did not take OCs. The mean duration of menstrual flow decreased significantly, from 5.8 to 4.4 days (P < .01), in the group of women taking OCs. The mean hematocrit increased significantly, from 35.8 to 37.8% (P = .014), in this group. In contrast, the women who did not take OCs had no significant changes in these indices.
Conclusion: In most women with leiomyomas, low-dose OC use provides the noncontraceptive benefit of a reduction in the duration of menstrual flow, with resultant improvement in hematocrit, without increasing uterine size.