Advanced Endometriosis and Pregnancy Outcomes

Mar 19, 2026

Advanced Endometriosis Linked to Pregnancy Risks—Yet Still Underrecognized

Key Points

Highlights:

Advanced (stage III–IV) endometriosis is associated with increased risks of adverse pregnancy outcomes; placenta previa and preterm birth emerge as the most consistent complications.
Adenomyosis and ART likely act as key confounders/modifiers

Importance:

Advanced endometriosis is associated with increased obstetric risk, while some complications (e.g., fetal growth restriction) may be driven more by coexisting adenomyosis.
Distinguishing disease-driven risk from surgical impact is essential for clinical decision-making.
Recognizing the role of adenomyosis can improve risk stratification and patient counseling.

What’s done here?

This is a narrative review evaluating whether pre-conception surgery for advanced endometriosis affects early pregnancy, obstetric, and neonatal outcomes.
The study also examines outcomes for women with advanced disease regardless of their surgical history and provides recommendations for pregnancy monitoring.

Key results:

Advanced endometriosis is associated with increased risks of miscarriage, preterm birth, placenta previa, and cesarean delivery.
Preterm birth risk remains elevated regardless of surgical status, suggesting a disease-driven mechanism.
Placenta previa shows the strongest and most consistent association, though the effect of surgery remains conflicting.
Hypertensive disorders (including preeclampsia) are increased, but not modified by surgery.
Fetal growth restriction is more strongly linked to coexisting adenomyosis than to endometriosis alone.
ART and adenomyosis act as major confounders, complicating interpretation of surgical outcomes.
Rare but severe complications (e.g., spontaneous hemoperitoneum, uterine rupture) are reported in advanced disease.

Strengths and Limitations

The review’s strengths include its focus on advanced (stage III–IV) disease and its consideration of key confounders such as adenomyosis and ART.
The limitations include the lack of robust high-quality evidence on surgical outcomes, along with small sample sizes and heterogeneity across existing studies.

From the Editor-in-Chief – EndoNews

"This review addresses a central and unresolved question in the management of advanced endometriosis: whether preconception surgery modifies obstetric risk.

While advanced disease is consistently associated with adverse pregnancy outcomes, the evidence synthesized in this article does not support a clear protective effect of surgical intervention.

Notably, the literature remains heterogeneous, with outcomes often differing between studies led by infertility specialists and those originating from surgical cohorts. These discrepancies likely reflect differences in patient selection, disease phenotype, treatment indications, and reproductive context, complicating interpretation and limiting generalizability.

The review further underscores the influence of key confounders—particularly adenomyosis and assisted reproductive technologies—which may independently drive obstetric risk and dilute the measurable impact of surgery. This challenges the prevailing assumption that reducing macroscopic disease burden alone will translate into improved pregnancy outcomes.

Collectively, the findings reinforce the need for caution in attributing obstetric benefit to surgical intervention in the absence of high-quality evidence.

Prospective, well-controlled studies are required to disentangle the relative contributions of disease severity, coexisting pathology, and treatment strategy. Until then, individualized, multidisciplinary care remains the most appropriate framework for managing pregnancies in women with advanced endometriosis."

Lay Summary

Advanced endometriosis (Stage III-IV) is a condition that can significantly affect a woman's pregnancy journey.

This review published in BMJ Reproductive Biology and Endocrinology, by Brunes et al. from Sweden, highlights that women with severe endometriosis face higher risks of complications such as miscarriage, preterm birth, and placenta previa compared to the general population.

Importantly, some complications—particularly fetal growth restriction—may be more closely related to adenomyosis, a condition that often coexists with endometriosis, rather than endometriosis itself.

Many women undergo surgery before pregnancy to improve symptoms or fertility. However, this review reports no consistent evidence that such surgery reduces pregnancy-related risks. For example, the risk of preterm birth remains elevated regardless of whether women had surgery or not. Similarly, conditions like high blood pressure in pregnancy do not appear to improve with surgical treatment and may instead be influenced by adenomyosis or assisted reproductive technologies.

The authors also highlight that endometriosis-related cysts can change during pregnancy and may sometimes resemble more serious conditions, making diagnosis challenging.

Overall, the findings emphasize the importance of individualized care. Women with advanced endometriosis should be closely monitored, with their medical history clearly documented and care coordinated by a multidisciplinary team.

“While advanced endometriosis is linked to higher risks of pregnancy complications, there is no consistent evidence that pre-conception surgery reduces these risks,” the authors conclude.