759: The contribution of maternal medical factors to the risk of SGA in a diverse community practice-based sample

759 The contribution of maternal medical factors to the risk of SGA in a diverse community practice-based sample Deborah Ehrenthal, Kristin Maiden, Louis Bartoshesky, Samuel Gidding Christiana Care Health System, Obstetrics and Gynecology, Newark, DE, Christiana Care Health System, Pediatrics, Newark, DE, AI Dupont Hospital for Children, Pediatric Cardiology, Wilmington, DE OBJECTIVE: To identify maternal medical contributors to the risk of delivering a small for gestational age (SGA) child and estimate their contribution to the overall rate of SGA in a diverse sample. STUDY DESIGN: We conducted a retrospective cohort study of singletons born 2004-2007 at a regional obstetrical hospital who received well child care from a large pediatric practice network using data derived from the electronic medical records of the mothers and their children. Children with a major birth defect (n 128) were excluded. Small for gestational age (SGA) was defined by a birthweight 10th percentile for sex and gestational age. Multivariable logistic regression was used to estimate the independent relations of pregnancy associated hypertension (HTN), chronic HTN, tobacco use, and inadequate gestational weight gain (GWG), based on IOM recommendations, to the odds of SGA, adjusting for other factors. Relative risk (RR) and population attributable fraction (PAF) were used to estimate their separate contributions. Data were analyzed using STATA IC10.1. RESULTS: Of 4728 dyads, 46% of mothers were African American, 44% privately insured; 584 (12.4%) were SGA. The odds of SGA were higher when mothers delivering at term had pregnancy associated HTN (aOR 1.6, 95%CI 1.1-2.2), chronic HTN (aOR 1.7, 95%CI 1.0-2.9), tobacco use (aOR 1.7, 95% CI 1.4-2.2), or inadequate GWG (aOR 1.6, 95%CI 1.3-2.1), adjusting for other factors. Obesity prior to pregnancy was associated with a reduced odds (aOR 0.6, 95%CI 0.4-0.7). The Table shows the RR and estimates of unadjusted PAF for SGA associated with each medical risk factor for babies born at term. The PAF was for 12% for pregnancy associated HTN when all deliveries were included. CONCLUSION: Only a portion of the risk of SGA at term in this cohort could be attributed to the contributions of hypertensive disorders, tobacco use, and inadequate GWG. Babies of obese mothers were protected. 760 Outcomes at a regional obstetrical hospital four years after implementation of the “39 week rule” Deborah Ehrenthal, Melanie Chichester, Matthew Hoffman Christiana Care Health System, Obstetrics and Gynecology, Newark, DE OBJECTIVE: To determine if early changes seen in gestational age distribution, NICU admission and stillbirth, continued four years after implementation of the “39 week rule” at a large regional obstetrical hospital. STUDY DESIGN: We conducted a retrospective cohort study using electronic obstetrical records from a large, regional obstetrical hospital of all singleton deliveries two years Before (2005-2006) and four years After-I (2008-2009), and After-II (20102011) the 2007 implementation of the “39 Week Rule”. Deliveries 34 weeks were excluded. Outcomes included gestational age (GA) in weeks completed and categorized as full term (39 weeks), early term (37-38 weeks) and late preterm (34-36 weeks); NICU admission, and stillbirth. Chi square and ANOVA were used to test significance. Data were analyzed using SPSS17. RESULTS: 13,009 women were delivered Before; 12,908 during the After-I and 12,309 during the After-II periods. There was a decrease in late preterm and early term deliveries and an increase in full term deliveries (Figure) after the intervention. The mean GA rose from 38.6 weeks (SD 1.4) Before to 38.9 weeks (SD 1.4) in After-I and 39.0 weeks (SD 1.4) in After-II (p 0.001). NICU admissions fell from 12.1% Before to 11.0% in After-I and 11.1% in After-II, (p 0.01). Stillbirth rate rose from 1.4 per 1,000 deliveries Before to 1.8 per 1,000 deliveries during After-I and 1.9 per 1,000 deliveries during After-II, but the difference was not statistically significant. CONCLUSION: Implementation of the “39 week rule” at a large regional obstetrical hospital was associated with a significant and sustained shift in the overall GA distribution for singleton births 34 or more weeks and a decrease in the rate of NICU admissions. There was a non-significant increase in the rate of stillbirths after the intervention.