Table 1_Previous caesarean delivery is associated with adverse obstetric and perinatal outcomes: a real-world cohort study of 26,843 singleton pregnancies.docx

Objective<p>To examine the association between a history of caesarean delivery and subsequent obstetric and perinatal outcomes.</p>Design<p>A real-world retrospective cohort study was conducted at a large tertiary maternity hospital in Shanghai, China.</p>Patients<p>Among 118,375 deliveries from January 2014 to August 2021, a total of 26,843 singleton pregnancies ≥28 weeks' gestation were included for analysis, comprising 11,359 women with a previous caesarean section (CS) and 15,484 with a prior vaginal delivery.</p>Main outcomes<p>Obstetric and perinatal outcomes including placenta previa, placenta abruption, abnormal placental morphology, emergency CS, elective CS, gestational diabetes mellitus (GDM), preeclampsia (PE), postpartum hemorrhage, preterm birth, low birth weight, congenital malformation, neonatal asphyxia, and congenital infection.</p>Results<p>After adjusting for relevant confounders, multivariable modified Poisson regression analyses showed that women with a previous CS history were associated with placenta previa [adjusted risk ratio (aRR): 1.71, 95% confidence interval (CI): 1.39–2.10], GDM (aRR: 1.28, 95% CI: 1.20–1.37), PE (aRR: 1.88, 95% CI: 1.56–2.27), elective CS (aRR: 1.35, 95% CI: 1.30–1.40), emergency CS (aRR: 1.24, 95% CI: 1.14–1.35), postpartum hemorrhage (aRR: 1.94, 95% CI: 1.45–2.58), preterm birth (aRR: 1.50, 95% CI: 1.36–1.65) and low birth weight (aRR: 1.37, 95% CI: 1.22–1.55).

In sensitivity analyses using propensity score matching and multiple imputation, the associations remained consistent.</p>Conclusion<p>A previous CS history is associated with adverse obstetric and perinatal outcomes, particularly placenta previa, GDM, PE, postpartum hemorrhage, preterm birth, and low birth weight. The association may vary by maternal age and history of miscarriage.</p>