Medical research has associated obesity with a long list of potential health problems and diseases. Among them is high-risk of pregnancy and delivery complications. According to new research published in the journal Human Reproduction, obese women have one leg up on slimmer peers. The research suggests slimmer women are more likely to develop endometriosis than obese women. 

Information for the study was collected over 20 years. More than 5,500 women with endometriosis (diagnosed with laparoscopy) were included. All women fell between 25 and 42 years old at the time they were enrolled for data collection. Participants were given a questionnaire to complete with questions about medical history, including their weight and height when they were 18 years old. The same information was collected at two-year intervals for the duration of the study. 

Women who fell into the morbidly obese category at the time of the study were less likely to develop endometriosis when compared to women at the lower end of normal BMI with obese women nearly 40% less likely to develop endometriosis. When doctors took BMI measurements at 18 into consideration, the correlation was stronger; women who reported being morbidly obese at 18 were 41% less likely to develop endometriosis. 

Researchers also noted that trying to become pregnant affected the risk of developing endometriosis as well. Obese women trying to become pregnant but having difficulty (infertile) were 62% less likely to develop endometriosis. The risk dropped even further in women who were morbidly obese at 18 – 77%. 

It is important to note that the correlation between endometriosis risk and obesity is clear, but that does not mean obesity is directly responsible for the reduction in risk. Researchers believe PCOS may have something to do with the correlation. Obese women are more likely to suffer from polycystic ovary syndrome or PCOS. The condition may slow the growth of endometriosis, which would account for the statistical differences in risk between morbidly obese and low normal women. 

Morbid obesity comes with potentially life-threatening side effects including increased risk for high blood pressure, type 2 diabetes, and sudden cardiac event. Only women with a low normal BMI were included in the study. Women with normal BMI's may not fall into the higher risk category. 


Source: D. K. Shah, K. F. Correia, A. F. Vitonis, S. A. Missmer. Body size and endometriosis: results from 20 years of follow-up within the Nurses' Health Study II prospective cohort. Human Reproduction, 2013; DOI: 10.1093/humrep/det120.