Interpregnancy Interval and Neonatal Outcomes

Abstract

Objectives: Interpregnancy interval (IPI), the time period between the end of one pregnancy and the conception of the next, can have a significant impact on maternal and infant outcomes. This study examines the relationship between interpregnancy interval and neonatal outcomes of low birth weight, preterm birth, and specific neonatal morbidities. Study Design: Retrospective cohort study comparing neonatal outcomes across 6 categories of IPI using data on 202,600 cases identified from Arizona birth certificates and the Newborn Intensive Care Program data. Comparisons between groups were made using odds ratios and 95% confidence intervals, and multivariable logisitic regression analysis. Results: Interpregnancy intervals of < 12 months and ≥ 60 months were associated with low birth weight, preterm birth, and small for gestational age births. The shortest and longest IPI categories were also associated with specific neonatal morbidities, including periventricular leukomalacia, bronchopulmonary dysplasia, intraventricular hemorrhage, apnea bradycardia, respiratory distress syndrome, transient tachypnea of the newborn, and suspected sepsis. Relationships between interpregnancy interval and specific neonatal morbidities did not remain significant when adjusted for birth weight and gestational age. Conclusions: Significant differences in neonatal outcomes (preterm birth, low birth weight, and small for gestational age) were observed between IPI categories. Consistent with previous research, interpregnancy intervals < 12 months and ≥ 60 months appear to be associated with increased risk of poor neonatal outcomes. Any difference in specific neonatal morbidities between IPI groups appears to be mediated through increased risk of low birth weight and preterm birth by IPI.