Induced Abortion After Previous Caesarean Section: A Scoping Review.

Background: Previous caesarean section (CS) is increasingly common among women undergoing induced abortion.

Aims: To map and analyse existing literature on abortion safety, outcomes and management in those with previous CS.

Materials and methods: Four databases were systematically searched from inception to July 2024. Primary human studies in English reporting on outcomes, safety or management of first- or second-trimester medical (MToP) or surgical (SToP) abortion in women with previous CS were included. Uterine rupture incidence was analysed cumulatively in the first and secondtrimesters by the number of CS and the type of prostaglandin used. Data on the efficacy and safety of MToP and SToP, including studies reporting on the management of abortion in the setting of abnormal placentation, were collected and analysed by theme.

Results: In total, 164 articles met inclusion criteria. Incidence of uterine rupture in first-trimester MToP was 0 of 2194 cases, in second-trimester misoprostol MToP in those with 1 previous CS was 0.5% (10/1910) and 2.2% (18/835) in women with ≥ 2 CS (p < 0.001). Mifepristone priming did not increase the rupture rate in second-trimester MToP (p = 0.77). Previous CS was a modest risk factor for retained products after MToP across both trimesters (OR 1.48, CI 1.29-1.70).

Conclusion: Medical and surgical abortion in the first and second trimester appears safe in women with prior CS; however, risks include uterine rupture, need for surgical intervention and haemorrhage from undiagnosed placenta accreta. Further research and guidance are needed on managing abortion after previous classical CS, ≥ 3 previous CS and those with abnormally invasive placenta.