Prior Uterine Surgery Linked to Higher Risk of Preterm Birth and Stillbirth

A new study published in April 2026 has found that uterine surgery before a first pregnancy is associated with a significantly increased risk of preterm birth and stillbirth in later pregnancies, with the risk rising with repeated procedures and varying by the type of surgery performed.

The research, published in the American Journal of Obstetrics and Gynecology, analyzed data from a large cohort of individuals who underwent uterine surgery prior to their first birth after 20 weeks’ gestation. Findings showed that such procedures were linked to a 51% higher adjusted odds of preterm birth (adjusted OR 1.51, 95% CI 1.47–1.55) and a notable increase in stillbirth risk.

The association was strongest among those who had undergone multiple uterine surgeries, suggesting a cumulative effect on reproductive outcomes. Researchers noted that the type of surgery also influenced risk levels, though specific procedural categories were not detailed in the available summaries.

Scientists involved in the study proposed two potential mechanisms for the observed risks: cervical weakening due to dilation during surgery, which may compromise the cervix’s ability to remain closed during pregnancy, and endometrial scarring that could impair placentation and contribute to stillbirth.

These hypotheses align with prior research indicating that procedures involving uterine evacuation or cervical manipulation may have lasting effects on uterine integrity and placental development. Earlier studies, including a 2016 analysis in the same journal, had noted a weaker association between surgical uterine evacuation and preterm birth, prompting calls for further investigation at the time.

The 2026 findings strengthen the evidence base linking pre-pregnancy uterine interventions to adverse perinatal outcomes, underscoring the importance of careful preoperative counseling and long-term follow-up for individuals undergoing such procedures, particularly those who may become pregnant in the future.

While the study establishes a clear association, researchers emphasized that it does not prove causation and called for additional research to clarify the biological pathways involved and to identify which specific surgical techniques carry the highest risk.

Healthcare providers are advised to consider reproductive history when evaluating patients for uterine surgery and to discuss potential implications for future pregnancies as part of informed consent processes.