27-05-2025
Preterm Birth Risk and Second-Trimester Medical Termination
Medical termination of pregnancy (mTOP) in the second trimester was considered safe and not significantly associated with the risk for future spontaneous preterm birth (sPTB).
METHODOLOGY:
Researchers conducted a single-centre cohort study to investigate the association between mTOP in the second trimester and the risk for subsequent sPTB in 1438 individuals who underwent an mTOP with mifepristone and/or misoprostol between 2008 and 2023.
The mean maternal age at the time of mTOP was 32.5 years; by December 2024, 1033 participants had a known subsequent pregnancy, and 405 did not.
Interpregnancy intervals were categorised as 0-3, 3-6, 6-12, 12-24, and more than 24 months; the gestational age at mTOP was 12 +0 -16 +0 , 16 +0 -19 +6 , and more than 20 weeks.
-16 , 16 -19 , and more than 20 weeks. The primary outcome was the rate of sPTB before 37 weeks in subsequent pregnancies, whereas secondary outcomes included rates of preterm births before 28, 32, and 37 weeks; miscarriage; repeated terminations; and variations in birth weight.
TAKEAWAY:
The incidence rate of subsequent sPTB before 37 weeks was 4.7% among singleton pregnancies and 16.7% among multiple pregnancies.
Participants with a short interpregnancy interval (< 3 months) had a higher incidence rate of sPTB than those with an interval of 12-24 months (6.8% vs 3.2%; adjusted odds ratio [aOR], 2.2; P = .2).
= .2). The incidence rate of sPTB was 5.9% and 2.6% for mTOP conducted at gestational ages of more than 20 weeks and less than 15 weeks, respectively (aOR, 2.2; P = .07).
= .07). The rate of subsequent sPTB before 37 weeks after excluding participants with prior sPTB before 37 weeks was 4.1% among singletons and 17.4% among multiples; when cases with prior curettage were excluded, the rate was 4.5% among singletons and 20.0% among multiples.
A higher gestational age at mTOP was significantly positively associated with subsequent sPTB before 37 weeks (β coefficient, 0.56; coefficient of determination, 0.31; P = .04).
IN PRACTICE:
"Second-trimester medical termination of pregnancy can be considered safe with regards to subsequent spontaneous preterm birth risk. As recommended following preterm and term birth, patient counseling should include the importance of allowing time for cervical remodeling to mitigate preterm birth risks, especially for those with a medical termination of pregnancy at higher gestational ages," the authors wrote.
SOURCE:
This study was led by Annabelle L. van Gils, MD, Amsterdam UMC - location University of Amsterdam, Department of Obstetrics and Gynecology, Meibergdreef, Amsterdam, the Netherlands. It was published online on May 19, 2025, in American Journal of Obstetrics and Gynecology.
LIMITATIONS:
This study was limited by the exclusion of subsequent pregnancies. Those who underwent mTOP for social reasons were not routinely referred for follow-up. As this study was conducted at the sole tertiary academic centre for prenatal diagnostics in North Holland, the study sample was representative, which may have affected the generalisability of results.
DISCLOSURES:
This study received no specific funding. Two authors reported receiving grants for PTB research and being part of a non-profit organisation that supports PTB research. One author reported being an advisor for prenatal screening in North Holland and chairing a related review committee from 2016 to 2023.
