Does endometriosis increase risk of unfavorable obstetric outcomes?

May 8, 2020
Bob Kronemyer
Bob Kronemyer

Freelance writer for Contemporary OB/GYN

An evaluation of evidence has concluded that the two most statistically significant unfavorable obstetric outcomes in women with endometriosis are placenta previa and preterm birth (PTB).

The study in the Brazilian Journal of Gynecology and Obstetrics reviewed literature in PubMed, PubMed, Web of Science and Scopus databases.

Of the 18 studies selected, five studies were of superior evidence quality and 13 studies of moderate evidence quality.

The largest study of superior quality of evidence for the assessment of obstetric and neonatal complications in women with endometriosis was published in 2017 in Acta Obstetricia et Gynecologica Scandinavica.

For this retrospective cohort study, data in Denmark’s National Health Register from women with clinically diagnosed endometriosis were assessed.

In the cohort of 19,331 deliveries (case group of 11,739 women and control group of 6,533 women), there were increased risks in the group diagnosed with endometriosis for preeclampsia (odds ratio [OR] 1.7; 95% confidence interval [CI]: 1.5 to 2.0); bleeding during pregnancy (OR 2.3; 95% CI: 2.0 to 2.5); premature placental abruption (OR 2.0; 95% CI: 1.7 to 2.3); placenta previa (OR 3.9; 95% CI: 3.5 to 4.3); premature rupture of membranes (RPMO) (OR 1.7; 95% CI: 1.5 to 1.8); placental retention (OR 3.1; 95% CI: 1.4 to 6.6);  PTB < 28 weeks (OR 3,1; 95% CI: 2.7 to 3.6); small for gestational age (SGA) (OR 1.5; 95% CI: 1.4 to 1.6); congenital malformation (OR 1.3; 95% CI: 1.3 to 1.4); and neonatal death (OR 1.8; 95% CI: 1.4 to 2.1).

A second large, high-quality, retrospective cohort study was also published in 2017, in the journal Fertility and Sterility, consisting of data from a Danish national registry of patients with singleton pregnancies. Of these patients, 1,213 were diagnosed with endometriosis, representing 1,719 pregnancies.

Women with endometriosis had an increased risk of PTB (OR 1.91; 95% CI: 1.16 to 3.15), preeclampsia (OR 1.37; 95% CI: 1.06 to 1.77) and cesarean delivery (OR 1.83; 95% CI: 1.60 to 2.09). But there was no connection to postpartum hemorrhage or SGA.

“This information is useful to alert obstetricians and patients about possible unfavorable obstetric outcomes,” said senior author Giuliana Annicchino, MD, who recently completed a residency program in ob/gyn at Hospital Israelita Albert Einstein in São Paulo, Brazil.

Initially, Dr. Annicchino thought the findings would link endometriosis to spontaneous abortion. “But then the results went the other way, showing that endometriosis is a disease that extends beyond the presence of ectopic endometrial implants,” she told Contemporary OB/GYN. “The condition of the endometrium can determine the quality of implantation and placental development, thus influencing obstetric outcomes.”

Dr. Annicchino and her colleagues intend to develop further studies about unfavorable obstetric outcomes in women with endometriosis that focus on the quality of the methodology, with adequate experimental designs and without bias such as in vitro fertilization (IVF).

“Because endometriosis is a diagnosis on the rise in our daily practice, we must increasingly study its implications and how it can affect clinical outcomes in our patients,” she said.

Disclosures:

Dr. Annicchino reports no relevant financial disclosures.