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The following is a summary of “Subsequent risk for preterm birth following second trimester medical termination of pregnancy,” published in the May 2025 issue of American Journal of Obstetrics & Gynecology by GILS et al. 

Medical termination of pregnancy with mifepristone and misoprostol was commonly performed, and high-quality cohort studies were warranted to explore its association with subsequent pregnancy outcomes following second-trimester procedures.  

Researchers conducted a retrospective study to assess the risk of spontaneous preterm birth in subsequent pregnancies following second-trimester medical termination of pregnancy.  

They performed a cohort study at Amsterdam University Medical Centre, location AMC, including individuals who underwent second-trimester medical termination of pregnancy between 2008 and 2023 using mifepristone and/or misoprostol and had a documented subsequent pregnancy through 2024. Individuals were excluded if termination involved other methods (e.g., cesarean section, hysterectomy, curettage, or foley catheter) or was indicated for intra-uterine fetal demise or previable prelabor rupture of membranes. The primary outcome was spontaneous preterm birth 37 weeks before the next pregnancy. Secondary outcomes included miscarriage before 16 weeks, repeated termination, and total, spontaneous, and iatrogenic preterm birth before 37, 32, and 28 weeks. Subgroup analyses were based on interpregnancy interval, gestational age at termination, and postpartum surgical procedures. Logistic regression was employed to calculate odds ratios (OR) and 95% CIs, adjusting for confounders. Singleton and multiple subsequent pregnancies were analyzed separately.  

The results showed that out of 1,438 eligible cases, 1,033 had a subsequent pregnancy with 986 outcomes available (singletons n=962, multiples n=24). In subsequent singleton pregnancies beyond 16 weeks, spontaneous preterm birth before 37 weeks occurred in 39/831 cases (4.7%), while in multiples, it occurred in 4/24 cases (16.7%). For singletons, spontaneous preterm birth rates were higher after an IPI less than 3 months compared to 12–24 months (6.8% vs 3.2%; aOR 2.2, 95%CI 0.69–7.4, P=0.2) and higher for GA over 20 weeks at mTOP vs 12+0 to 15+6 weeks (5.9% vs 2.6%; aOR 2.2, 95% CI 0.92–5.4, P=0.07), though these were not statistically significant. However, a linear regression including GA at mTOP as a continuous variable showed a significant positive association with subsequent spontaneous preterm birth (B=0.56, R² =0.31, P=0.04).  

Investigators concluded that second-trimester medical termination of pregnancy was generally safe concerning subsequent spontaneous preterm birth risk, and counseling should emphasize appropriate intervals for cervical remodeling, particularly after higher gestational age terminations.   

Source: ajog.org/article/S0002-9378(25)00317-5/fulltext