606: Risk of recurrent preterm birth among women according to change in paternity

Abstract

OBJECTIVE: The relationship of paternity change between pregnancies and preterm (PTB) risk is unclear with conflicting findings, particularly with respect to recurrent PTB. Here we examine the risk of repeated PTB among women with a change in paternity. STUDY DESIGN: The study population was drawn from California singleton live births occurring from 2005 through 2011. All mothers and infants were in a birth cohort file maintained by the California Office of Statewide Health Planning and Development, which includes linked birth certificate and hospital discharge records. The sample was restricted to women who delivered their first and second infants between 20 and 44 weeks gestation and where there was known paternity and interpregnancy interval. The final sample included 186,724 mothers. Risk of PTB (< 34 weeks, 34 - 36 weeks) and early term (37 and 38 weeks) delivery in the second pregnancy was calculated for mothers who did or did not change partners between pregnancies with women who delivered both pregnancies at term (39 - 44 weeks) and did not change partners between births. Odds ratios and their 95% confidence intervals were calculated using logistic regression models, adjusting for race, age, smoking status, maternal education, Medi-Cal payment for delivery, hypertension and interpregnancy interval. RESULTS: Relative to women who delivered at 39 weeks or later in the second pregnancy and did not change paternity, women who delivered their first pregnancy before 37 weeks, irrespective of change in paternity, were at elevated risk of PTB in the second pregnancy. In most comparisons these PTB risks were higher for women where there was not a change in paternity (Table). CONCLUSION: Women with a previous PTB were at increased risk of having another PTB in their second pregnancy. However, after adjusting for maternal factors, women who changed partners between their first and second pregnancy were at lower risk of delivering before 39 weeks than women who did not change partners. Findings suggest pathophysiological underpinnings including paternal contributions to PTB. (Table Presented).