TOPLINE: 

Uterine surgery before first birth was associated with increased odds of preterm birth and stillbirth, and this association was stronger in women who had undergone two or more surgeries.

METHODOLOGY: 

• Researchers conducted a cohort study examining all women who had their first birth between January 2007 and December 2019 in New South Wales, Australia. A total of 520,050 women were included in the final analysis, based on two routinely collected datasets.
• They included 76,486 women who underwent any uterine surgery prior to the registered birth, including curettage for miscarriage or termination, hysteroscopy procedures, management of cervical dysplasia, operative hysteroscopy, procedures involving a long-acting reversible contraceptive device, uterine evacuation, and endometrial ablation.
• The primary outcomes were preterm birth, defined as live birth before 37 weeks of completed gestation, and stillbirth, defined as fetal death at or beyond 20 weeks’ gestation. Outcomes were compared with women without prior surgery.
• Outcomes were stratified by gestational age (< 24 weeks, 24-31 weeks, and 32-36 weeks) and by number of procedures (one vs two or more).

TAKEAWAY: 

• Women with prior uterine surgery were more likely than women without prior surgery to deliver preterm ( 11.5% vs 7.6%; adjusted odds ratio [aOR], 1.51; 95% CI, 1.47-1.55) and were more likely to experience a stillbirth (aOR, 1.39; 95% CI, 1.26-1.53).
• Two or more prior surgical procedures were linked to increased odds of preterm birth (aOR, 2.00; 95% CI, 1.90-2.11) and stillbirth (aOR, 1.77; 95% CI, 1.49-2.09) compared with one prior procedure (aOR, 1.38 [95% CI, 1.33-1.43] for preterm birth and 1.29 [95% CI, 1.16-1.44] for stillbirth).
• Major hysteroscopic procedures showed the strongest association with risk for preterm birth (aOR, 1.80; 95% CI, 1.67-1.94), and endometrial ablation was associated with the highest odds of stillbirth (aOR, 3.66; 95% CI, 2.07-6.47).
• For preterm birth, the association was strongest at the earliest gestational ages: < 24 weeks (OR, 2.06; 95% CI, 1.85-2.30), 24-31 weeks (OR, 1.83; 95% CI, 1.72-1.95), and 32-36 weeks (OR, 1.43; 95% CI, 1.39-1.47). For stillbirth, the association was significant at less than 24 weeks’ gestation (OR, 1.64; 95% CI, 1.28-2.10).

IN PRACTICE: 

“These findings are hypothesis generating. Prospective indication-matched studies are needed to further explore the meaning of these findings for nulliparous women. It might be that some of these women should have better access to transvaginal cervical length measurement through the midtrimester to target interventions against extreme preterm birth and early stillbirth,” the authors wrote.

SOURCE: 

The study was led by Emily C. Olive of the Discipline of Obstetrics Gynaecology and Neonatology Faculty of Medicine and Health at the University of Sydney, New South Wales, Australia. It was published online on April 9, 2026, in the American Journal of Obstetrics & Gynecology.

LIMITATIONS: 

The analysis could not distinguish whether the observed increased risks resulted from the surgical procedures themselves or from the underlying conditions that had prompted surgery. Women who underwent surgery outside of New South Wales prior to pregnancy were not included in this study. Additional unmeasured confounding factors may have influenced the observed associations. 

DISCLOSURES:

No funding was provided for this study. The authors disclosed having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.