741 Estimating risk factors for developmentof preeclampsia in gravid teensArthur Baker1, Sina Haeri2

1Memorial Health University Medical Center, Obstetrics andGynecology, Savannah, GA, 2Baylor College of Medicine,Obstetrics and Gynecology, Houston, TXOBJECTIVE: Some population-based studies have implicated youngmaternal age as an independent risk factor for preeclampsia; however,data are lacking with respect to the specific maternal characteristicsrendering this group as high risk. Our objective was to estimate riskfactors for development of preeclampsia in pregnant teens.STUDY DESIGN: In a cohort study of all nulliparous teen (�18 yearsold) deliveries over a 4-year period at one institution, we identified allcases of preeclampsia using the National Working Group for Hyper-tension in Pregnancy diagnostic criteria. Group comparisons andanalysis was performed using Fishers exact, Student’s t-test, and lo-gistic regression modeling.RESULTS: Of the 730 included teen deliveries, 65 (9%) women devel-oped preeclampsia, and demonstrated a higher pre-pregnancy bodymass index (BMI) when compared with controls (32.9 vs. 30.3 kg/m2,p�0.002). Maternal obesity (BMI � 30 kg/m2, RR: 1.6, 95% CI: 1.0-2.8) and gestational weight gain above the Institute of Medicine(IOM) recommended levels (RR: 2.6, 95% CI: 1.5-4.4) were associ-ated with higher risk for development of preeclampsia. When evalu-ating by severity or onset of disease, weight gain above IOM recom-mended levels appeared as the single strongest factor associated withthe development of mild (n�58) or late onset (n�54) disease (RR:2.5, 95% CI: 1.4-3.4).CONCLUSION: Maternal obesity and higher than IOM recommendedgestational weight gain place the gravid teen at increased risk for pre-eclampsia. The modifiable nature of these risk factors permit the pos-sibility of intervention and prevention. The absence of obesity’s im-pact on early onset or severe disease in our cohort further supports arole for an underlying genetic predisposition in these women.

742 Pharmacodynamics of low-dose aspirin in pregnancyAvinash Patil1, Elizabeth Thames1, Andra James1

1Duke University Medical Center, Obstetrics and Gynecology, Durham, NCOBJECTIVE: Low-dose aspirin (LDA) is prescribed to reduce the risk ofpreeclampsia. Physiologic changes during pregnancy may limit aspi-rin’s effectiveness. The objective of this study was to assess the phar-macodynamic effects of LDA on platelet function throughout preg-nancy.STUDY DESIGN: A subset of subjects enrolled in a prospective study ofhemostatic factors in pregnancy who took LDA (81 mg daily) werecompared with the subjects who did not. Indications for LDA were ahistory of preeclampsia, poor reproductive outcome, or increased riskof thrombosis. None of the subjects continued LDA postpartum. Dur-ing the study, maternal blood samples were obtained at the end of thefirst and second trimester, and at 6 weeks postpartum (baseline). Theeffects of LDA on platelet function was assessed using light transmit-tance platelet aggregometry and an automated platelet function ana-lyzer (PFA-100). Platelet aggregometry was tested with four agonists:ADP, collagen, epinephrine, and arachidonic acid (AA). The PFA-100closure time was measured using both collagen/epinephrine and col-lagen/ADP cartridges. Kruskal-Wallis and Wilcoxon nonparametrictests were used to characterize platelet function at each timepoint.RESULTS: Of the 125 subjects enrolled, 5 received LDA during preg-nancy. Median maternal age and weight were similar between the twogroups. When the aspirin and no aspirin groups were compared, all 4agonists and the collagen/epinephrine PFA test detected a differencein platelet function (Table). Among subjects in the LDA group, therewas significant variance in aggregation between pregnancy and post-partum values with collagen (�2�0.01) and AA (�2�0.01), but notADP, epinephrine, or the PFA-100 tests. Individual timepoint com-

parisons revealed that platelet function was unchanged between thefirst and second trimester.CONCLUSION: Low dose aspirin has a consistent effect on platelet func-tion throughout pregnancy. Increased dosing of aspirin is not neces-sary to maintain its pharmacodynamic effects in pregnancy.

743 Hypertensive disease in pregnancy: an examinationof ethnic differences and the Hispanic ParadoxAvis Carr1, Maria Small2, Trace Kershaw3, Haywood Brown4

1Duke University School of Medicine, Duke University Department ofObstetrics and Gynecology, Durham, NC, 2Duke University Medical Center,Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Durham,NC, 3Yale University School of Public Health, Epidemiology and PublicHealth, New Haven, CT, 4Duke University School of Medicine,Department of Obstetrics and Gynecology, durham, NCOBJECTIVE: The Hispanic Paradox refers to the epidemiological find-ing that Hispanics in the US have better health outcomes than theaverage population despite what their aggregate socioeconomic de-terminants would predict. The aim of this study was to evaluate ob-stetric outcomes for a multiethnic population with hypertensive dis-eases.STUDY DESIGN: We performed a retrospective review of parturientswith hypertensive disease delivering at Duke University Medical Cen-ter in 2007. We analyzed maternal sociodemographic characteristicsand ethnic differences in hypertensive disease types using Chi Square.We assessed the role of race and ethnicity on maternal and neonataloutcomes through a series of logistic regression analyses.RESULTS: 3,124 women delivered during the study period, and 9 %had hypertensive diseases in pregnancy. There were significant racialand ethnic differences in presentation (Chi-square� 39.11, p�.001)with gestational hypertension more common in Whites, chronic hy-pertension in African Americans, and mild preeclampsia in Hispan-

www.AJOG.org Academic Issues, Antepartum Fetal Assessment, Genetics, Hypertension, Medical-Surgical-Disease Poster Session V

Supplement to JANUARY 2012 American Journal of Obstetrics & Gynecology S329