Poster Session V Prematurity, Physiology www.AJOG.org

respiratory distress syndrome, and feeding difficulties were lower inthe +FLM group; however, composite neonatal morbidity did notdiffer.CONCLUSION: In patients with PPROM, delivery after confirmation ofFLM at 32-336/7 weeks compared with expectant management until34 weeks may prevent maternal infection without increasingneonatal morbidity. These findings warrant confirmation in a pro-spective study.

Maternal and neonatal outcomes of PPROM:delivery after confirmed fetal lung maturity vs.expectant management until 34 weeks

Data represented as %.

*Multivariable adjustments include antenatal corticosteroid administration,

chronic hypertension, diabetes and labor induction; **Includes cho-

rioamnionitis and endometritis; yIncludes mechanical ventilation, culture

proven early-onset sepsis, neonatal death, Grade III/IV IVH, HIE, seizures,

NEC; zIncludes mechanical ventilation, RDS, TTN.

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Maternal magnesium sulfate treatment is not associatedwith serum calcium levels of preterm neonateGeum Joon Cho1, Ji Eun Lee1, Hye-Ri Hong2, Soon-Cheol Hong1,Young Sook Hong3, Hai-Joong Kim1, Min-Jeong Oh11Department of Obstetrics and Gynecology, Korea University College ofMedicine, Seoul, Republic of Korea, 2Department of Obstetrics andGynecology, Inha University Hospital, Inha University College of Medicine,Incheon, Republic of Korea, 3Department of Pediatrics, Korea UniversityMedical Center, College of Medicine, Korea University, Seoul, Republic ofKorea

OBJECTIVE: It is well known that magnesium plays an important rolein calcium homeostasis. Recently, FDA is advising health care pro-fessionals against using magnesium sulfate (MgSO4) treatmentbecause MgSO4 treatment beyond 5-7 days to pregnant women cancause low calcium and bone abnormalities in the neonate. However,the effect of maternal MgSO4 treatment on neonatal calcium ho-meostasis is inconsistent among studies. The aim of this study was todetermine the association between maternal MgSO4 treatment andneonatal calcium level.STUDY DESIGN: This is a retrospective study of 570 pregnant womenwith preterm birth and their paired neonates. Case group of 101neonates whose mothers had received intravenous MgSO4 treatmentwere compared to control of 469 neonates whose mothers had no

S356 American Journal of Obstetrics & Gynecology Supplement to JANUARY

MgSO4 treatment. Neonatal calcium levels were measured in um-bilical cord blood after delivery.RESULTS: Neonatal calcium levels were lower in case group thancontrol. However, the incidence of hypocalcemia (total serum cal-cium level<7mg/dL) was not different between two groups. Amultiple linear regression model showed that maternal preeclampsia,gestational age at delivery, beta-mimetic tocolytic treatment,maternal GDM and delivery mode were independent predictors ofneonatal calcium levels. However, maternal MgSO4 treatment wasnot associated with serum neonatal calcium levels.CONCLUSION: Our results indicate that maternal MgSO4 treatmentmay not cause low calcium levels in preterm neonates. Furtherstudies are needed to evaluate the long term effect of maternalMgSO4 treatment on neonatal bone abnormalities.

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Prenatal IL1 receptor blockade prevents motor but notcognitive deficits in a mouse model of preterm intrauterineinflammation and perinatal brain damageIrina Burd1, Tahani Dada1, Rudhab Bahabry1, Haitham Baghlaf1,Mikhail Pletnikov1, Karin Blakemore1, Michael Johnston11Johns Hopkins University School of Medicine, Baltimore, MD

OBJECTIVE: Exposure to preterm intrauterine inflammation (PIUI)results in a spectrum of motor and cognitive deficits in the offspring.Using a mouse model of PIUI, we have demonstrated that IL1 re-ceptor antagonist (ILA) blocked fetal cortical neuronal injury asso-ciated with PIUI. The objective of these studies was to determine ifmaternal pretreatment with ILA would prevent offspring morbidityand neurologic injury associated with PIUI.STUDY DESIGN: Using a mouse model of PIUI, there were 3 groups: 1)intraperitoneal (IP) normal saline (NS)+IU NS (negative control); 2)IP NS+IU lipopolysaccharide (LPS) (positive control); 3)IP ILA+IULPS, with ILA administered at 10 mg/kg 30min prior to LPS.Offspring mortality, growth and neurodevelopment (motor andcognitive test battery) were evaluated at postnatal days (PND) 5, 9and 13 (LPS¼15 litters, NS¼5 litters and ILA+LPS¼6 litters).Expression of 29 neuronal, astrocyte and oligodendrocyte-specificgenes was analyzed at PND18, using QPCR.RESULTS: A significant difference in growth was observed. At PND13,the average weight was 10.4g (NS), 9.7g (LPS) and 9.1g (ILA)(p<0.01, ANOVA). While there was no difference in expression ofneuronal, astrocyte and oligodendrocyte-specific markers betweengroups, offspring in the ILA group demonstrated an overallimprovement in motor but not cognitive neurodevelopmentaltesting, as compared to LPS-exposed group (p<0.05, ANOVA).CONCLUSION: Maternally administered ILA, while it leads to growthretardation, appears to prevent motor but not cognitive deficits inthe offspring. These studies provide evidence that motor andcognitive deficits, as a result of exposure to intrauterine inflamma-tion, may involve divergent pathways. Furthermore, while ILA’s ef-fect on neurologic sequelae associated with PIUI was evident in thisstudy, the risk of growth retardation may mitigate against its clinicalutility as a therapeutic agent for prevention of motor deficits.(Funded by KO8HD073315).

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Vaginal versus cesarean delivery for breech in latepreterm: how do neonatal outcomes compare?Teresa Sparks1, Aaron Caughey2, Yvonne Cheng11University of California, San Francisco, Division of Maternal Fetal Medicine,San Francisco, CA, 2Oregon Health and Science University, Department ofObstetrics & Gynecology, Portland, OR

2014