ajog.org Poster Session IV

measurement is more effective in identifying and managing the smallfor gestational age (SGA) fetus.STUDY DESIGN: A decision-analytic model was created using TreeAgesoftware to compare third trimester US and fundal height screeningfor SGA in a cohort of 100,000 singleton, low-risk pregnancies at 28-32 weeks’ gestation. Suspected SGA by fundal height would befurther investigated with US. Fetuses screened positive for SGA byUS would undergo additional antepartum surveillance, which wasassumed to reduce the risk of stillbirth by 66% but lead to a 10%increase in the late preterm birth rate. Outcomes included stillbirth,late preterm birth, neonatal death, and cerebral palsy. All probabil-ities were derived from the literature. We calculated quality-adjustedlife years (QALYs) to compare strategies, accounting for maternaland neonatal utilities.RESULTS: Third-trimester US would prevent 45 stillbirthscompared to fundal height screening. However, screening with USwould increase the late preterm birth rate, ultimately leading to 5more neonatal deaths and 9 more cases of cerebral palsy. Despitelower rates of neonatal morbidity and mortality with fundalheight screening, third-trimester US was ultimately the moreeffective strategy as it maximized total QALYs. Univariate sensi-tivity analyses showed that US remained the optimal strategy untilantepartum surveillance could only reduce the risk of stillbirth by18%.CONCLUSION: Weighing the benefits of preventing stillbirth againstthe risks of late preterm birth in the setting of increased antepartumsurveillance, third-trimester growth US is more effective than fundalheight screening for SGA. This difference is largely attributed toultrasound’s increased sensitivity and resultant ability to preventstillbirth in our model. Further analyses are needed to determinewhether this strategy would be cost-effective in a low-risk popula-tion.

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Does corticosteroid therapy impact fetal pulmonaryartery blood flow in women at risk for preterm birth?William Lindsley1, Richard Hale1, Ashley Spear1,Kimberly Destefano1, Jasvant Adusumalli1, Sina Haeri21St. David’s Women’s Center of Texas, Austin Maternal Fetal Medicine,Austin, TX, 2Baylor College of Medicine, Obstetrics and Gynecology,Houston, TXOBJECTIVE: Maternal corticosteroid administration in pregnancy isknown to enhance fetal lung maturity in at risk fetuses. The aim ofthis study was to test the hypothesis that corticosteroid therapy altersfetal pulmonary blood flow in pregnancies at risk for preterm birth(PTB).STUDY DESIGN: We prospectively evaluated main fetal pulmonaryartery (MPA) blood flow in pregnant women at risk for PTB andtreated with corticoidsteroids, compared to an uncomplicated cohortwithout steroid therapy. The Doppler indices of interest includedPeak Systolic Velocity (PSV), Resistive Index (RI), Pulsatility Index(PI), Systolic/Diastolic ratio (S/D ratio), Acceleration Time (AT), andAcceleration Time/Ejection Time Ratio (AT/ET ratio), with the latterserving as the primary outcomes due to its stability irrespective ofgestational age.RESULTS: When compared with controls, fetuses treated with corti-costeroids demonstrated significantly decreased pulmonary arteryacceleration time (32.025 � 6.98 vs. 37.11ms + 8.59ms, p¼0.01),while all other indices remained similar. Contrary to findings by Kimet al (Am J Perinatol. 2013 Nov;30(10):805-12.), we found no dif-ference in pulmonary blood flow between fetuses who developedRDS and those that did not (31.56 � 6.842 vs. 32.36 � 7.265, p¼0.76).CONCLUSION: Our data demonstrate altered fetal pulmonary bloodflow with corticosteroid therapy, likely due to increased arterialelastance brought on by medication effect, which leads to thedecreased acceleration time. Contrary to a recent report, we did notobserve any Doppler differences in fetuses with RDS, which un-derscores the need for further examination of this proposed asso-ciation.

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Racial disparities in the association between totalgestational weight gain and gestational diabetes mellitus bypre-pregnancy BMIYinJiao Ma1, Betelihem Tobo1, Leping Wan1, George Macones2,Jen Jen Chang11Saint Louis University, College for Public Health and Social Justice,Department of Epidemiology, Saint Louis, MO, 2Washington University, SaintLouis, MOOBJECTIVE: To examine racial disparities in the relationship betweengestational weight gain (GWG) and gestational diabetes mellitus(GDM).STUDY DESIGN: This is a population-based, retrospective cohortstudy based on the Florida birth certificate data from 2005 to 2012.The study sample included 1,926,852 women without pre-preg-nancy diabetes who delivered singleton pregnancies at 37-44 weeksof gestation in Florida. Body mass index (BMI) was categorizedaccording to IOM recommendations: underweight, normal, over-weight, and obese. According to the IOM’s recommended guide-line, we divided total GWG into three groups: over, within, andbelow recommendations. Data were stratified by maternal race/ethnicity and pre-pregnancy BMI. A multivariable binary logisticregression model was used to estimate odds ratios (OR) and 95%confidence intervals (95% CI) controlling for maternal age, height,nativity, education, parity, tobacco use during pregnancy, com-posite maternal medical risk factor, WIC enrollment, and prenatalcare adequacy.RESULTS: The association between GWG and GDM varied bymaternal pre-pregnancy BMI and race/ethnicity. GWG belowrecommendation was associated with increased odds of GDM for

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Poster Session IV ajog.org

Non-Hispanic White, Asian/Pacific Islander, Hispanic, and mix racewomen. The strength of association was greater among Non-His-panic White and Asian/Pacific Islander women than women of otherrace groups. However, for Non-Hispanic Black women, GWG belowrecommendation was associated with decreased likelihood of GDM.For non-Hispanic White and Asian/Pacific Islander women, GWGover recommendation was associated with decreased likelihood ofGDM; yet, for Non-Hispanic Black women it was associated withincreased odds of GDM.CONCLUSION: Our study showed racial disparities in the associationbetween GWG and GDM. The long-term consequences of GWGover recommendation, particularly among Non-Hispanic Blackwomen, have important public health implications and merit addi-tional research.

S354 American Journal of Obstetrics & Gynecology Supplement to JANUARY

2015