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 5,000 births per year between 2015–2022 were analysed. 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 4 132 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 was 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 suggests 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.