Preeclampsia and Risk of Apnea of Prematurity in Late Preterm Infants: A Retrospective Cohort Study

Preeclampsia (PE) is characterized by antenatal hypoxia and inflammation, which may impair neonatal respiratory control. However, its association with apnea of prematurity (AOP) in late preterm infants remains unclear. This study aimed to test the hypothesis that maternal PE is an independent risk factor for AOP in late preterm infants.

This retrospective cohort study was conducted at Yamanashi Central Hospital between January 2017 and June 2025. Singleton pregnancies delivered between 34^ + 0 and 36^ + 6 weeks of gestation were included. Early-onset PE was defined as diagnosis before 34 weeks of gestation, and late-onset PE as diagnosis at or after 34 weeks. Multivariable logistic regression analyses were performed to evaluate the association between PE and AOP, adjusting for potential confounders. In Model 1, PE was analyzed as a binary variable. In Model 2, subjects were categorized into three groups: early-onset, late-onset, and no PE.

A total of 470 mother-infant pairs were analyzed. Among them, 23 women experienced early-onset PE, and 34 experienced late-onset PE. The overall incidence of AOP was 27.9% (131/470). In Model 1, PE was associated with a higher AOP risk (adjusted odds ratio [aOR], 2.44; 95% confidence interval [CI]: 1.21-4.90). In Model 2, early-onset PE was significantly associated with AOP (aOR: 3.42; 95% CI: 1.20-9.72), whereas late-onset PE was not (aOR: 1.88; 95% CI: 0.75-4.73).

PE, particularly early-onset, was significantly associated with AOP. Incorporating maternal PE status into perinatal risk stratification may help identify late preterm infants at elevated AOP risk and guide timely intervention.