biological variation rather than abnormal placental function. Sinceplacental malperfusion is less likely to be present with low amnioticfluid but normal fetal growth, expectant management, in the absenceof fetal heart rate changes suggesting umbilical cord compression, islikely to be safe.

698 Detected vs undetected small-for-gestational-age:a multicenter retrospective study at tertiary centersSuneet Chauhan1, Eugene Chang2, Elena Igwe3, Adam Sandlin4,Joshua Dahlke5, Hind Beydoun6, E.F. Magann7, CandeAnanth8, Kristi Anderson9, Alfred Abuhamad1

1Eastern Virginia Medical School, Department of Obstetrics and Gynecology,Norfolk, VA, 2Medical University of South Carolina, Department ofObstetrics and Gynecology, Charleston, SC, 3Temple University Hospital,Department of Obstetrics and Gynecology, Philadelphia, PA, 4University ofArkansas for Medical Sciences, Department of Obstetrics & Gynecology, LittleRock, AR, 5Naval Medical Center Portsmouth, Department of Obstetrics andGynecology, Portsmouth, VA, 6Eastern Virginia Medical Center, GraduateProgram of Public Health, Norfolk, VA, 7UAMS, Department of Obstetricsand Gynecology, Little Rock, AR, 8Columbia University, Departmentof Obstetrics and Gynecology, New York, NY, 9Naval Medical CenterPortsmouth, Department of Obstetrics and Gynecology, Portsmouth, VAOBJECTIVE: ACOG practice bulletin on intrauterine growth restriction(IUGR), states that small-for-gestational age (SGA) is detected in 50%of cases and those undetected cases have higher mortality. The pri-mary purpose of this multi-center study was to determine factorslinked to SGA (birth weight � 10% gestational age [GA]) being de-tected vs. undetected; the secondary purpose, determine whether SGAdetection significantly influences composite neonatal morbidity(CNM).STUDY DESIGN: At 4 centers, we identified all non-anomalous singletons,with sonographic exam before 22 weeks and SGA (birth weight � 10%for GA using Alexander nomogram) that delivered in 2009. If IUGRwas suspected antenatally, SGA was considered detected and unde-tected otherwise. An adjusted log-linear model was constructed toidentify variables associated with SGA detection and a multivariatelog-linear model, to examine the net effect of SGA detection on CNM(thrombocytopenia, RDS, proven sepsis, grade III/IV IVH, seizure, ordeath). Both analyses were adjusted for 5 variables: maternal age, eth-nicity, nulliparity, body mass index (BMI) at 1st visit and smoking.RESULTS: There were 11,487 births and 8% (929) were SGA that metthe inclusion criteria. Though the detection rate varied (18-36%),overall 25% of SGA were detected antenatally. After adjustment for 5variables, detection varied significantly by ethnicity. Likelihood ofsonographic estimate fetal weight (SEFW) and birth weight variedsignificantly between the 2 groups (Table). CNM occurred in 13% andafter adjusting for 5 variables, it varied significantly with BMI at 1stvisit and whether SGA was detected (43%) vs undetected (22%; OR2.24, 95% CI 1.62, 3.12).CONCLUSION: Only 1 out of 4 SGA was detected antenatally and themodifiable variable that could improve detection is SEFW within 4weeks of birth. A prospective multi-center is warranted to determineif antenatal detection of SGA significantly lowers CNM.

699 The influence of maternal body composition(MBC) and gestational weight gain (GWG) on fetalbody composition (FBC) in the third trimesterClare O’Connor1, Nadine Farah2, Vicky O’Dwyer3,Mairead Kennelly4, Bernard Stuart4, Michael Turner5

1The Coombe Women and Infants University Hospital, School of Medicine& Medical Science UCD Centre For Human Reproduction, Dublin, Ireland,2Coombe Women and Infants University Hospital, UCD Centre for HumanReproduction, Dublin, Ireland, 3Coombe Women & Infants UniversityHospital, UCD Centre for Human Reproduction, Dublin, Ireland, 4CoombeWomen & Infants University Hospital, UCD Centre for HumanReproduction, Dublin, Ireland, 5Coombe Women and Infants UniversityHospital, UCD Centre for Human Reproduction,, Dublin, IrelandOBJECTIVE: To determine if MBC or GWG influenced the FBC in thethird trimester of pregnancy.STUDY DESIGN: After Gestational Diabetes (GDM) had been excludedwith a diagnostic Glucose Tolerance Test at 28 weeks gestation womenwith a healthy singleton pregnancy were recruited at their conve-nience. Consent was obtained. At 28 and 37 weeks gestation, MBC wasassessed directly by advanced bioelectrical impedance analysis andindirectly by measuring BMI and GWG. FBC was assessed by fetal softtissue measurement antepartum and birth weight immediately post-partum. Statistical analysis included the use of Pearson correlationcoefficients and multiple regression analysis.RESULTS: In 231 women, the fetal abdominal circumference (AC) at37 weeks correlated positively with maternal height (r�0.2, p�0.006)and weight (r�0.2, p�0.007) in the first trimester as well as maternalfat mass (r�0.1,p�0.018) and fat-free mass (r�0.2,p�0.001) mea-sured at 28 weeks gestation. The fetal midthigh subcutaneous tissue at37 weeks correlated positively with GWG in the third trimester(r�0.2,p�0.003) and with maternal fat mass at 28 weeks gestation(r�0.1,p�0.04). GWG in the third trimester did not correlate withbirth weight or the AC.CONCLUSION: In nondiabetic women, maternal weight in the first tri-mester but not GWG in the third trimester influenced the AC. GWGdid influence midthigh measurements but not birth weight. Thesefindings indicate that MBC influences the distribution as well as themass of fetal adiposity. Whether interventions before or duringpregancy can modify these influences remain to be determined.

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 S311