ajog.org Poster Session IV

evaluations, respectively. Overall, there was a 6-fold variation inL&D Triage visits (mean 21, SD 5.7, range 6-36), with the least andmost busy days having 28.6% and 171.4% of average volume. WDshad, on average, 39.6% more visits than WE days.(Table) Volumesvaried 2.4 to 3.3-fold on WDs and 2.9 to 4.5-fold on WE days.Significant variation in volume and Triage evaluation type alsooccurred through the day, with DELADM as the predominatereason 2-10 AM, and OP assessments predominating thereafter(Figure 1, p<.001). Delivery admissions demonstrated similar butmore variable pattern compared with the entire cohort. WDs had45.2% more deliveries, on average, than WE days. Volumes varied3.8 to 17-fold on WDs and 4 to 11-fold on WE days. We found an18-fold variation in deliveries between the least to most busy days(mean 8.2, SD 3.0, range 1-18), with these having 12.2% and219.5% of average volume.CONCLUSION: There is substantial variation in daily and hourly L&DTriage activity. If not planned for, this variability could strainavailable resources and negatively impact care. Further study of theeffect of surges in L&D triage and delivery volumes on pregnancyoutcomes, and of optimal methods to provide surge capacity in theL&D setting, are needed.

L&D Triage volumes and variation according to day of week.

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Does external environment increase the rate of pretermbirth and small for gestational age?Kelly Ruhstaller1, Sindhu Srinivas1, Michelle Greene2,Scott Lorch2, Jamie Bastek11Maternal and Child Health Research Program, University of PennsylvaniaPerelman School of Medicine, OBGYN, Philadelphia, PA, 2Children’sHospital of Pennsylvania, Neonatology, Philadelphia, PAOBJECTIVE: Although previously studied in the internal medicineliterature, the impact of potentially modifiable exposures such asgeographic environment on obstetrical outcomes remains poorlyunderstood. Therefore our objective was to determine whether zip-code level demographics along with individual-level maternal

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characteristics are associated with preterm birth (PTB) < 37 weeksand small for gestational age (SGA) <10% in Philadelphia County.STUDY DESIGN: Retrospective cohort study using linked birth certif-icate data from all singleton deliveries between 16-44 weeks inPhiladelphia county (2005-2009) (N¼85,520). For each outcome, acomprehensive list of individual-level variables related to de-mographics and personal medical and obstetric history was studiedwith univariable analyses; statistically significant variables wereretained in the final individual-level multivariable model. Zip-codelevel variables relating to population demographics, neighborhoodcrime, structural decline, social stress, education / employment, andsocial capital were assessed for each outcome; significant zip-codelevel variables were serially applied to the individual-level multi-variable model to determine whether they retained significance. Forall analyses, p<0.001 was significant.RESULTS: The population rate of PTB was 18.70% (n¼15,994) andSGA was 12.34% (n¼10,544). Individual-level variables includingmaternal age, BMI, education, maternal vascular disease, PTL/PPROM, fetal sex, oligo/ polyhydramnios, obstetric history, and racewere retained in the final individual-level multivariable model. Zip-code level variables that retained statistical significance in the finalmultivariable models are listed (Table).CONCLUSION: These citywide data suggest that environmental vari-ables in Philadelphia county are associated with PTB and SGA. Inaddition to targeting individual-level variables, our success indecreasing rates of these adverse pregnancy outcomes may dependon population level strategies to modify external environment.

Zip code level variables and preterm birth or smallfor gestational age

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Maternal bisphenol a (BPA) exposure programs maleoffspring hepatic insulin signaling protein expressionKristina Galyon1, Farnoosh Farshidi1, Michael Ross1, Mina Desai1,Juanita Jellyman11LABioMed at Harbor-UCLA Medical Center, Obstetrics and Gynecology,Torrance, CAOBJECTIVE: The obesogenic and diabetogenic effects of the envi-ronmental toxin BPA, particularly during critical windows ofdevelopment, are well-recognized. Using a rat model of maternal

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BPA we have demonstrated glucose intolerance in male, but notfemale offspring. Liver plays a central role in the control of glucoseproduction and regulation of insulin secretion. We hypothesized thatmaternal BPA exposure disrupts hepatic insulin signaling, contrib-uting to glucose intolerance in the male offspring. We determinedthe protein expression of key hepatic insulin signaling molecules(glucose transporter, insulin receptor and its downstream target).STUDY DESIGN: Rat dams were given ad libitum access to filtereddrinking water (Control) or drinking water with BPA (5mg/L; BPA)from two weeks prior to mating and throughout pregnancy andlactation. Offspring litters were standardized to four males and fourfemales and nursed by the same dam. Liver tissue was collected from 1day old (P1) and 3 week old (P21) male and female offspring forprotein expression (Western Blot) of glucose transporter 2 (GLUT-2),insulin receptor beta (IR-b) and insulin receptor substrate-1 (IRS-1).RESULTS: At P1, male BPA offspring showed decreased liver proteinexpression of GLUT-2 (0.5-fold), with no changes in IR-b or IRS-1.However at P21, male BPA offspring exhibited increased liver pro-tein expression of IR-b (2-fold) and IRS-1 (1.5-fold), with no dif-ferences in GLUT-2 protein expression. Female BPA offspringshowed no significant changes in insulin signaling protein expressionat either age.CONCLUSION: The results suggest that maternal BPA impairs hepaticinsulin signaling leading to increased risk of diabetes in maleoffspring. We propose that the mechanism of sex-specific BPA-ef-fects on offspring glucose homeostasis is secondary to BPA estro-genic effects during development. Together with human studies,these findings suggest that maternal BPA exposure should be limitedduring pregnancy and lactation.

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The association of race and gender with respiratorydistress syndrome at caesarian deliveriesLaura Hitchings1, Morgan Kearney1, Gabrielle Kattan1,John Thorp11University of North Carolina, Department of Medicine, Raleigh, NCOBJECTIVE: RDS in the premature newborn has shown to beaffected by gender, race and mode of delivery with particular sig-nificance in Caucasian males. However the incidence of thesecomplications have not been stratified across the entire thirdtrimester, grouping the infants by both gender and race. Thepurpose of this study was to investigate the rates of RDS inCaucasian males, born via Caesarian Section in comparison to theirfemale and ethnic counterparts.STUDY DESIGN: A retrospective cohort study of infants born via ce-sarean section was performed utilizing the MFMU Cesarean Registry.Infants were grouped according to gender, maternal ethnic group(White, Black or Hispanic) and gestational age at delivery. Maternaldemographics were collected and diagnosis of respiratory distresssyndrome (RDS) was the primary outcome. Rates of RDS werecompared across the six groups from 24 to 42 weeks gestation andfurther comparisons were made for white males specifically.RESULTS: A total of 55,811 infants met inclusion criteria for thisstudy. A diagnosis of RDS was made in 5875 (10.5%) infants, withpercentages decreasing as the GA approached term. White malesrepresented 22.5% of the population and 13.6% of this cohort werediagnosed with RDS. When compared to all other infants, whitemales were shown to have significantly greater risk for RDS from 32to 39 weeks gestation. Odds ratios were calculated and corrected forother known risk factors for RDS.CONCLUSION: On review of a national sample of births at variousgestational ages, an increased risk for RDS has been shown in whitemale infants born via cesarean section. This risk occurs across thelate preterm gestations and extends into term. These findings sup-port previous research that both race and gender are independent

S328 American Journal of Obstetrics & Gynecology Supplement to JANUARY

risk factors for RDS in the neonate and should be considered whenplanning a caesarian delivery.

The graph shows rates of RDS in white males versus all othergroups. The values marked with an asterisk, convey a significanthigher rate of RDS.

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High altitude increases mid-gestation maternal PAPP-A2Leah Lamale-Smith1, Suhong Tong2, Virginia Winn1,Lorna Moore11University of Colorado, Obstetrics and Gynecology, Aurora, CO, 2Universityof Colorado, Biostatistics and Informatics, Aurora, COOBJECTIVE: The frequency of preeclampsia and reduced infant birthweight increases at high altitude, which has been attributed toincreased placental hypoxia. Pregnancy-associated plasma protein A2(PAPP-A2) is a pregnancy related insulin-like growth factor bindingprotein-5 (IGFBP-5) protease that is elevated in preeclampsia andup-regulated by hypoxia in placental explants. Therefore, we soughtto evaluate the effect of the relative hypoxia of high altitude onPAPP-A2.STUDY DESIGN: Plasma PAPP-A2 levels were determined longitudi-nally in normotensive women at pregnancy weeks 20 and 36 whoresided either at 400 m (low) or 3600 m (high) altitude in Bolivia.There were 24 subjects in each cohort. All high and half the lowwomen were of Andean ancestry as determined using gene markers.Blood was collected by standard venipuncture and plasma stored at-80�C. Immunoblot analysis was performed with anti-PAPP-A2(R&D; 1:2,000), densitometry of immunoreactive bands determinedusing Biorad Chemi Doc, and data analysis done in Prism 6.0b orSAS. Statistical significance was set at P< 0.05.RESULTS: The high and low altitude women were of similar age,gravidity, and nonpregnant BMI. Birth weights were similar in thetwo groups and all high and most (80%) low-altitude womendelivered at term. PAPP-A2 rose from 20 to 36 weeks of gestation atboth altitudes (p<0.0001 and 0.0003, respectively). Levels wereelevated in the high compared to the low-altitude subjects at 20 butnot 36 weeks whether or not values were adjusted for percent An-dean ancestry. P¼0.0112 and 0.1233, respectively.CONCLUSION: Altitude associated hypoxia in the absence of pre-eclampsia increases PAPP-A2 at mid-gestation but to a lesser extentnear term. Relative hypoxia at high altitude may account for increasedPAPP-A2 levels at mid-gestation, although increasing gestational agehas a greater effect. This early elevation of PAPP-A2may contribute tothe increased incidence of preeclampsia at high altitude.

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