Pregnancy outcomes among women with endometriosis and fibroids: registry linkage study in Massachusetts

Background: Endometriosis and uterine fibroids are common gynecologic conditions associated with a greater risk for infertility. Previous research has suggested that these conditions are associated with adverse pregnancy outcomes, potentially because of increased utilization of fertility treatments. Objective: Our objective was to investigate whether women with a history of endometriosis or fibroids had a greater risk for adverse pregnancy outcomes and whether this risk varied by infertility history and fertility treatment utilization. Study Design: Deliveries (2013–2017) recorded in Massachusetts’ vital records were linked to assisted reproductive technology data, hospital stays, and all-payer claims database. We identified endometriosis and fibroids diagnoses via the all-payer claims database before index delivery. Adjusted relative risks for pregnancy complications were modeled using generalized estimating equations with a log link and Poisson distribution. The influence of subfertility or infertility and assisted reproductive technology was also investigated. Results: Among 91,825 deliveries, 1560 women had endometriosis and 4212 had fibroids. Approximately 30% of women with endometriosis and 26% of women with fibroids experienced subfertility or infertility without utilizing assisted reproductive technology, and 34% of women with endometriosis and 21% of women with fibroids utilized assisted reproductive technology for the index delivery. Women with a history of endometriosis or fibroids were at a greater risk for pregnancy-induced hypertension, preeclampsia, or eclampsia (endometriosis relative risk, 1.17; fibroids relative risk, 1.08), placental abnormalities (endometriosis relative risk, 1.65; fibroids relative risk, 1.38), and cesarean delivery (endometriosis relative risk, 1.22; fibroids relative risk, 1.17) than women with no history of those conditions. Neonates born to women with a history of endometriosis or fibroids were also at a greater risk for preterm birth (endometriosis relative risk, 1.24; fibroids relative risk, 1.17). Associations between fibroids and low birthweight varied by fertility status or assisted reproductive technology (P homogeneity=.01) and were stronger among noninfertile women. Conclusion: Endometriosis or fibroids increased the risk for adverse pregnancy outcomes, possibly warranting differential screening or treatment.