Previous cesarean section and major complications during surgical abortion: A national multicentre case-control study.

OBJECTIVES

To investigate the association between previous cesarean section (CS) and major complications during first- and second-trimester surgical abortion.

STUDY

DESIGN

We conducted a national retrospective case-control study using prospectively collected data from all MSI Australia surgical abortion facilities between 2016 and 2024. Individuals undergoing surgical abortion between 5 + 0 and 23 + 6 weeks' gestation were eligible. Cases were procedures complicated by hemorrhage ≥ 500 mL, transfusion, uterine perforation, hospital transfer, laparotomy, laparoscopy, or hysterectomy. Each case was matched to four gestation-matched controls (±3 weeks) through a blinded process. A composite severe outcome included hysterectomy, laparotomy, intensive care admission, disseminated intravascular coagulation, or massive hemorrhage (≥2000 mL). Logistic regression estimated adjusted odds ratios (aORs) with 95% confidence intervals (CIs).

RESULTS

Among 159 major-complication cases and 636 gestation-matched controls, a history of previous CS was more common among cases than controls. After adjustment for age, gestational age, parity and body mass index, previous CS remained associated with increased likelihood of being a case (aOR 2.6, 95% CI 1.7-4.0). Odds of being a case increased with increasing numbers of previous CS (aOR 2.0 per cesarean, 95% CI 1.5-2.6). Previous CS was more common among composite severe adverse outcome cases than controls (OR 9.56, 95% CI 4.34-21.04).

CONCLUSION

A history of previous CS was more common among cases than controls, with the odds of being a case increasing according to the number of prior CS. These findings may assist counseling, pre-procedure assessment and perioperative planning for patients with a history of cesarean birth.

IMPLICATIONS: Previous cesarean section was more common among cases than controls, including cases with severe adverse outcomes. Increasing numbers of prior cesarean sections were associated with higher odds of being a case. These findings may inform counseling and perioperative planning.