Uterine leiomyoma and its association with menstrual pattern and history of depo-medroxyprogesterone acetate injections

BACKGROUND AND AIM Despite the high prevalence of uterine leiomyoma, according to recent review studies there is uncertainty and a paucity of information regarding its predisposing or protective factors. The aim of this study was to assess the possible association between menstrual cycle pattern and occurrence of surgically treated myomas and also to check if depo-medroxyprogesterone acetate (DMPA) injection earlier in reproductive life can affect the later occurrence of myomas needing surgical treatment. METHODS In a case-control study in Ardabil, 85 women with definite diagnosis of surgically treated uterine leiomyoma and 154 community controls were enrolled. Possible predictors of myoma including menstrual cycle and menstrual bleeding patterns were assessed. Data were analyzed using SPSS software (SPSS, IBM, Somers, NY). Odds ratios were used as the main statistic in assessing the strength of observed associations. RESULTS Mean age of the participants was 41.8 ± 8.5 years. Length of menstrual cycle was associated with myoma and a higher likelihood of myoma was observed among those having shorter menstrual cycles (P < 0.05). Number of menstrual bleeding days was also associated with surgically treated myoma and longer bleeding periods increased the likelihood of myoma (P < 0.05). Only one of the eight women who had a history of depo-medroxyprogesterone acetate injections had developed surgically treated uterine leiomyoma and the others belonged to the control group without a history of surgical treatment for uterine leiomyoma. CONCLUSION Menstrual cycle pattern is associated with developing leiomyomas requiring surgical treatment. DMPA, other than its role in myoma treatment, is also assumed to have a role in preventing myomas, but due to the small sample size in this study, larger scale prospective trials are needed in the future.