Obesity Tied to Heavy Menstrual Bleeding, Delayed Repair in Womb Lining

Jacqueline Maybin, BSc, MBChB, PhD

New research from a study examining both mice and humans suggests obesity was linked to heavier periods and delayed repair of the womb lining.

While the study did not examine ways to mediate this apparent risk, results point to associations between increased body weight and greater menstrual blood loss that could subsequently affect the repair of womb lining in these women.

"Our findings suggest that women with obesity may experience heavier periods due to increased local inflammation and delayed repair of their womb lining. It would be really interesting to investigate the reasons behind this to further our understanding of womb function in the presence of obesity and develop more effective, evidence-based treatments,” said Jacqueline Maybin, BSc, MBChB, PhD, a senior research fellow and consultant gynecologist in the MRC Centre for Reproductive Health at the University of Edinburgh, in a statement.

With an interest in learning more about how body mass index might influence menstrual blood loss, Maybin and a team of colleagues from the University of Edinburgh designed the current study in an attempt to quantify the BMI and MBL in women not receiving hormone therapy and with regular menstrual cycles. Recruiting women from clinics in NHS Lothian, which is 1 of 14 regions of NHS Scotland, investigators identified 121 women with fully completed pictorial-based assessment charts.

The mean age of study participants was 42.8 (19-55) years, the mean BMI was 26.9 (17.2-43.6), 39.7% had fibroids present on ultrasound, and just 1 patient had a diagnosis of diabetes. For the purpose of analysis. Of note, 25% of participants were considered obese. Investigators defined heavy menstrual bleeding as a PBAC score greater than 80 mL.

Upon analysis, investigators found heavy menstrual bleeding was present among 63% of participants. In regression analyses, results pointed to a weak positive association between PBAC score and BMI (P=.02). In multiple regression, investigators found only the presence of fibroids added significantly to BMI in predicting PBAC (P=.004) and BMI remained borderline significant when adjusting for fibroids (P=.051).

Based on these results and the heterogeneity of human participants, investigators subsequently designed a mouse model of simulated menstruation. In mice, investigators simulated menstruation and found diet-induced obesity resulted in delayed endometrial repair. Additionally, BrdU staining of uterine tissue in mice revealed decreased proliferation during menstruation in the lumina epithelium of mice on a high-fat diet.

When assessing hypoxia-regulated genes, results also indicated consistently higher mean values of VEGF, ADM, LDHA, and SLC2A1 in the endometrium of women with obesity and in uteri of mice with increased weight compared to controls, but investigators noted none of these associations reached statistical significance.

"Although it is difficult to make strong recommendations based on this study alone, a common-sense approach would be to offer weight-loss support to women with a high BMI experiencing heavy periods. However, this should not replace investigation and treatment of other underlying causes for heavy bleeding. This should form part of personalised treatment recommendations to be considered by both patients and doctors."

This study, “Obesity is associated with heavy menstruation that may be due to delayed endometrial repair,” was published in the Journal of Endocrinology.