RESULTS: Cervical volume (CV) and cervical length (CL) were moderately well correlated over gestation (r¼0.5). Mean (SD) CV in the three GA ranges was 70.9 (23.5), 73.9 (18.3), and 71.7 (11.0) cm 3 . CV differed by maternal parity between 16-19.9 weeks only (58.9 vs. 77.7cm 3 p¼0.04). While CL was significantly correlated with gestational age (p¼0.001), CV was not. (p¼0.39). CV repro- ducibility was high, with inter-observer variability of 4-6%. CONCLUSION: Cervical volume appears to remain stable over gesta- tion, as opposed to cervical length, which is correlated with gesta- tional age. Cervical volume may therefore be a useful adjunct to cervical length in assessing risk of preterm birth. 664 Preterm labor in twin gestations: a point of care test to identify impending preterm delivery and intra-amniotic infection Kyung Joon Oh 1 , Roberto Romero 2 , Bo Hyun Yoon 1 1 Seoul National University, Seoul, Korea, Republic of, 2 Perinatology Research Branch, NICHD/NIH/DHHS, Detroit, MI OBJECTIVE: Preterm labor in twin gestations presents diagnostic and therapeutic challenges. Intra-amniotic infection is presents in approximately 10%-20% of gestations, and may affect one or both sacs. The purpose of this study was to determine if a commercially available point of care (POC) test for the detection of matrix met- alloproteinase-8 (MMP-8) could identify patients with intra-amni- otic infection and adverse outcome. STUDY DESIGN: Amniotic fluid (AF) was retrieved from both sacs in 90 twin gestations with preterm labor and intact membranes (34 weeks). The fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas. Intra-amniotic infection was defined as positive AF culture result of one or both sacs in a twin pair. AF was analyzed with the POC test. Non-parametric and survival techniques were used for analysis. RESULTS: 1) Intra-amniotic infection of at least one sac was present in 10% (9/90) of patients; 2) A positive MMP-8 rapid test had a sensitivity of 100% (9/9), a specificity of 70% (57/81), a positive predictive value of 27% (9/33) and a negative predictive value of 100% (57/57) in the identification of intra-amniotic infection. All of the 15 sacs with a positive AF culture (9 patients; both sacs in 6 cases and the presenting sac only in 3 cases) had a positive MMP-8 rapid test; 3) Women with a positive MMP-8 rapid test had a significantly higher rate of adverse outcome (including a lower gestational age at birth, shorter amniocentesis-to-delivery interval, acute histologic chorioamnionitis and funisitis) than those with a negative POC test even after adjusting for gestational age at amniocentesis. Delivery within 7 days occurred in 82% (27/33) of patients with a positive POC test, but only in 31% (17/55) of patients with a negative test (p<0.001). CONCLUSION: A POC test for MMP-8 can identify women at risk for intra-amniotic infection and adverse outcome in twin pregnancies with preterm labor and intact membranes. 665 Maternal vitamin D supplementation on infant growth Shuqin Wei 1 , Weiguang Bi 2 , Line Leduc 1 1 Uinversity of Montreal, Montreal, QC, Canada, 2 CHU Ste-Justine Research Center, Montreal, QC, Canada OBJECTIVE: The objective is to evaluate the effects of prenatal vitamin D supplementation on infants growth. STUDY DESIGN: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs). Inclusion criteria were RCT design evaluating maternal vitamin D supplementation in pregnant women on infant outcomes. RESULTS: Seven RCTs met the inclusion criteria. Data from the above 8 trials involving 1053 women found that women who received vitamin D supplements during pregnancy had a higher mean birth weight (g) (mean difference 124.20, 95% CI 103.78 to 144.62), larger body length (cm) (mean difference 0.30, 95% CI 0.18 to 0.41), larger head circumference (cm) (mean difference 0.52, 95% CI 0.36 to 0.68). There were larger skinfold thickness (cm) (mean difference 0.21, 95% CI 0.17 to 0.24). Follow-up the infants to 3-month old and 1-year old, the infants’ weight, length and head circumstance were larger in the supplementation group vs. control group. CONCLUSION: The evidence from this meta-analysis suggests that maternal vitamin D supplementation during pregnancy improve offspring growth at birth, 3-month-old and 1-year-old. 666 Using pattern-recognition software to evaluate intrapartum fetal heart rate (FHR) tracings George Saade 1 1 for the Eunice Kennedy Shriver NICHD MFMU Network, Bethesda, MD OBJECTIVE: Visual interpretation of FHR is prone to human error. We sought to evaluate the association between neonatal adverse outcome and intrapartum FHR characteristics using computerized pattern recognition. STUDY DESIGN: Secondary analysis of a multi-center trial of intra- partum fetal ECG monitoring in women with singletons >36 weeks. The last 60 mins of stored digital FHR (scalp electrode) were analyzed by PeriCALM Patterns. Files missing >30 mins before delivery were excluded. The neonatal adverse outcome was a com- posite of any of: intrapartum fetal death, neonatal death, Apgar score  3 at 5 minutes, neonatal seizure, cord artery pH  7.05 plus base deficit  12 mmol/L, intubation for ventilation at delivery, or neonatal encephalopathy. Valid cord artery pH required both artery and vein values confirmed based on a pre-specified algorithm and outcomes were reviewed centrally. The association between various FHR patterns (as defined by NICHD criteria) and the primary outcome was evaluated by univariate analysis, and by logistic regression after adding FHR variability. RESULTS: 9,848 patients were included and the neonatal outcome occurred in 1.2%. Several FHR characteristics were associated with the outcome (Table). Very few cases had FHR variability <5 bpm and variability overall was not associated with the outcome regard- less of the cutoff used or the duration. Accelerations were associated with better outcomes, while prolonged decelerations were associated with worse outcomes. Variable decelerations were common and were less frequent in neonates with the outcome, regardless of nadir or duration. Number and percent of the FHR tracing with late decelerations were both higher in the group with the primary outcome. Except for prolonged decelerations, adding variability to decelerations in the model did not improve the association. CONCLUSION: In this well-characterized intrapartum cohort with rigorous cord gases and outcome ascertainment, FHR pattern- recognition software identifies patterns that are associated with Poster Session IV ajog.org S352 American Journal of Obstetrics & Gynecology Supplement to JANUARY 2016