Women with Endometriosis Have Higher Risk of Complications in Pregnancy, Japanese Study Shows

Women with Endometriosis Have Higher Risk of Complications in Pregnancy, Japanese Study Shows

A study of pregnant Japanese women shows that those with endometriosis have a significantly increased risk of complications during pregnancy, even among women treated with assisted reproductive technology therapy.

The study, “Obstetrical Complications in Women with Endometriosis: A Cohort Study in Japan,” was published in the open access journal PLOS One.

It is generally accepted that women with endometriosis have more difficulties conceiving and, as a consequence, are often treated with infertility treatments, including assisted reproductive technology therapy.

A prospective group study evaluating the impact of endometriosis in Japanese women and their pregnancy outcomes, however, was lacking. In these types of studies, researchers follow, over a certain period of time, a group of similar individuals (called cohorts) to understand how a certain variable — in this case the presence or absence of endometriosis and infertility therapy — impacts a specified outcome.

A team of researchers aimed to investigate the incidence of adverse pregnancy outcomes and the influence of endometriosis. Specifically, researchers determined how endometriosis impacts pregnancy outcomes by comparing Japanese women with and without endometriosis.

They performed a prospective analysis of the incidence of obstetrical complications in women with endometriosis using data from the Japan Environment & Children’s Study (JECS). This is an ongoing prospective birth cohort study set up to evaluate the effects of several environmental factors on children’s health and development.

Of the 9,186 pregnant women included in the study, 4,119 (44.8 percent) had obstetrical complications, and 330 women were diagnosed with endometriosis before pregnancy.

Researchers observed that women with endometriosis presented higher risk for complications in pregnancy when compared to women without a history of endometriosis. The complications included pre-term premature rupture of the membranes (PROM), when the amniotic sac breaks prior to the onset of labor, and placenta previa, when the placenta blocks (partially or completely) the neck of the uterus, interfering with the normal delivery of a baby.

Researchers found that the increased risk of preterm PROM and placenta previa was still present in women with endometriosis, even if they received assisted reproductive technology therapy.

The authors concluded that “the present study is the first to show a significant impact of endometriosis on the incidence of obstetrical complications after adjusting for the confounding of assisted reproductive technology therapy.”