Researchers find association between obesity and HMB

A study in the Journal of Endocrinology suggests that obesity is associated with heavy menstrual bleeding (HMB) in women of reproductive age. “Researching how obesity impacts menstrual blood loss is important to improve the ways we prevent and treat the debilitating symptom of heavy menstrual bleeding,” said Jacqueline Maybin, MBChB, PhD, senior research fellow and honorary consultant gynecologist at the MRC Centre for Reproductive Health at the University of Edinburgh, in a recent press release.¹

Researchers analyzed data from 121 reproductive-aged women attending gynecologic clinics at NHS Lothian in Scotland, all of whom reported regular menstruation of 21 to 35 days.² For 2 months, they had not been using hormonal contraceptives and had no exogenous hormone exposure. The average age of participants was 42.8 years (P=0.43) and, on average, a body mass index (BMI) of 26.9 (17.2-43.6).

Each woman’s height and weight measurements, and a fully completed pictorial-based assessment chart (PBAC), were used to conduct the analysis. Obesity was defined as a BMI above 30. HMB was defined as total menstrual blood loss of 80mL or greater over the course of one cycle.

The participants returned a fully completed PBAC that contained pictorial representation of graded staining across different absorbencies of menstrual towels and tampons. They completed the PBAC each time they changed their pad or tampon over the course of one menstrual period. HMB was defined as a PBAC score of 80mL or greater.

HMB was observed in 63% of participants. In regression analysis, a weak but statistically significant association was observed between menstrual PBAC score and BMI (P=0.2). The presence of fibroids was the only factor that added significantly to BMI in predicting menstrual PBAC score (P=0.04).

Due to the multiple factors that can influence menstrual blood loss, researchers also conducted a mouse study to analyze the role of weight on endometrial repair during menstruation. Its findings revealed that a high-fat diet significantly delayed endometrial repair.

Mice were fed a normal diet (n= 6) or a high-fat diet (n= 10) before simulation of menstruation. Mice on a high fat diet (n = 6) had a significantly increased body weight (P < 0.0001) with a mean weight of 34 g vs a mean weight of 23 g in mice maintained on a normal diet (n = 10).

Researchers found significantly increased body weight and delayed endometrial repair at stimulated menstruation in the mice on a high-fat diet. At the time of menstrual repair, an examination of the uteri of the high-fat mice showed decreased luminal epithelial cell proliferation and increased local inflammatory mediators indicating that increased body weight disrupts endometrial function during menstruation that results in increased menstrual blood loss.

“This will facilitate evidence-based shared decision making between clinicians and patients regarding lifestyle adjustments in the management of this common symptom,” the authors concluded.

References

1. Obesity linked to heavy menstrual bleeding for reproductive age women. News release. Endocrine Today. April 9, 2021.
2. Reavey J, Walker C, Murray A, et. al. Obesity is associated with heavy menstruation that may be due to delayed endometrial repair. Eur J Endocrinol. 249. 249.2 (2021): 71-82. https://doi.org/10.1530/JOE-20-0446