705: Previous adverse outcome of pregnancy and risk of preterm birth in subsequent birth

Abstract

Women with a preterm birth (PTB) are at risk of PTB in subsequent pregnancies. However, less is known about women with previous term birth but other adverse pregnancy outcomes. Here, we evaluate risk of PTB among a population of women with previous term birth but other adverse pregnancy outcome. The sample was drawn from 2005-2012 singleton live born infants included in a birth cohort file maintained by the California Office of Statewide Health Planning and Development. The sample was restricted to women with two live births and previous delivery between 39-42 weeks. Women with fetal anomalies in either birth were excluded. Logistic regression was used to calculate the risk of PTB in the second birth for women with previous fetal demise/termination, placenta previa, placental abruption, preeclampsia, small for gestational age (SGA) infant, or infant death. The file did not differentiate between fetal demise and termination. Risks were adjusted for race/ethnicity, age, education, body mass index, insurance coverage, smoking status, hypertension, preeclampsia, diabetes, infection, drug/alcohol use, mental illness, anemia, interpregnancy interval, placenta previa, placental abruption, and SGA (all recorded for second birth). 282,196 women were included. Of the women with any previous poor outcome, 4.2% had a PTB (Figure). A history of an adverse pregnancy outcome conferred a 1.2-fold increased risk of PTB and a 1.4-fold increased risk of PTB <32 weeks. Women with a fetal demise/termination between their two live births, and women with a previous infant who died were at highest risk of PTB in their second delivery (aRRs 1.8). Previous placental abruption or a SGA infant also increased the risk of the second birth occurring preterm (aRRs 1.5-1.8) (Table). Previous placental abruption, SGA infant, and infant death increased the risk of PTB in the subsequent live birth among a population of women with no prior PTB. Previous fetal demise/termination also a risk for PTB in subsequent pregnancies, however indication for termination was unavailable in the dataset.View Large Image Figure ViewerDownload Hi-res image Download (PPT)