Risk of preterm birth and peripartal complications after first trimester termination of pregnancy: a retrospective cohort study of 35,897 singleton births

PURPOSE: The objective of this study was to explore whether a history of termination of pregnancy (TOP) in births after 2015 in a high income setting is still linked to preterm birth (PTB) and peripartal complications. METHODS: 35,897 singleton births from a perinatal center with approximately 5000 births per year between 2015 and 2022 were analyzed. Patients with a history of first trimester TOP (TOP < 15 weeks) were compared to those who had never had a TOP. A two-step statistical approach using Chi-squared analysis and forward-step multiple logistic regression was used to explore the relationship. RESULTS: 4132 individuals (11.51%) had a history of first trimester TOP. Our findings suggest an association between past TOP and a higher risk for PTB (OR = 1.44, 95% CI [1.25-1.67], p < 0.001). This increases with the number of TOP, six or more TOP were associated with the highest odds ratio for spontaneous PTB (OR = 5.21, 95% CI [1.88-14.46], p = 0.002). The risk for PTB did not differ between methods. Furthermore, our data suggest an association between past TOP and placental retention (OR = 1.25, 95% CI [1.03-1.52],p = 0.022). CONCLUSION: These findings underscore the importance of still recognizing prior TOP as a risk factor in obstetric care. The results may inform targeted counseling and the development of preventative strategies to mitigate maternal and fetal morbidity.