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www.AJOG.org Fetus, Prematurity Poster Session III

449 The role of betamethasone and fetal lung maturityesting in late preterm cesarean deliveriesulie Phillips1, öDüL Amburgey1, Anna Benvenuto1,

arjorie Meyer1, Eleanor Capeless1

University of Vermont, Obstetrics, Gynecology,nd Reproductive Sciences, Burlington, VermontBJECTIVE: Respiratory morbidity (RM) remains a leading cause ofeonatal intensive care (NICU) admissions in late preterm infants,specially those born by cesarean delivery (CD). Recent evidence sug-ests antenatal betamethasone (BMZ) may reduce RM in this group.ur objective was to evaluate the benefit of BMZ or assessment of fetal

ung maturity (FLM) when planning CD in the late preterm infant.TUDY DESIGN: We performed a retrospective chart review of CD be-ween 35�0 and 36�6 weeks gestation between Jan 2005 and Mar009. Maternal and neonatal records were analyzed for demograph-cs, gestational age, delivery indications, amniocentesis, BMZ andeonatal outcomes. RM included need for oxygen, surfactant, intu-ation, or the diagnosis of TTN, PPHN, or RDS. Fisher’s exact andilcoxen rank tests were used for statistical analysis.

ESULTS: 53 patients were identified. Indications for CD included pre-ia, abnormal antenatal testing, abruption, rupture of membranesnd malpresentation. The average GA at delivery was 36.1 weeks.2.1% had RM. 21 (39.6%) underwent amniocentesis for FLM. 3% ofhose with a mature FLM had RM. 11 (52.4%) patients had an imma-ure FLM. 8 received BMZ; none of these infants had RM. 3 did noteceive BMZ, 1 had RM. 32 patients were delivered without FLMesting. 11 empirically received BMZ with 45.5% RM. 21 did not re-eive BMZ with 38.1% RM, p�0.16. Those with an immature FLMere younger than those with a mature FLM (36.0 vs 36.4 weeks,�0.04).ONCLUSION: Those patients undergoing indicated cesarean deliveryt 35 to 37 weeks had a high rate of neonatal RM. This persisted evenn those with mature FLM testing. RM was low in those with an im-

ature FLM who subsequently received BMZ. BMZ did not decreaseates of RM in patients without FLM testing. Routine use of BMZ inhe late preterm infant does not appear to decrease overall RM.

ates of Respiratory Morbidity with use of FLM or BMZ

Amnio- mat(10)

Amnio- imm(11) p

�BMZ(11)

�BMZ(21) p

A wks 36.4 36.0 0.04 35.9 36.3 0.07.........................................................................................................................................................................................

M (%) 33.3 9.1 0.25 45.5 38.1 0.78.........................................................................................................................................................................................

002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.615

450 The effect of magnesium sulfate on activity of matrixetalloproteinase -9 in fetal cord plasma and human

mbilical cord vein endothelial cellsrad M. Dolinsky1, Danielle L. Ippolito1, Deborah Tinnemore1,raig M. Zelig1, Jonathan D. Stallings1, Peter G. Napolitano1

Madigan Army Medical Center, Tacoma, WashingtonBJECTIVE: Clinical epidiomologic evidence suggests that magnesiumulfate used for preterm labor may ameliorate the risks of fetal neu-ologic injury. The biologic plausibility of this is poorly understood.

atrix metalloproteinases are complex zinc dependent enzymes. Ma-rix metalloproteinase -9 (MMP9) levels are elevated in preterm laboratients and in patients with preterm amniorrhexis. There is evidencehat MMP9 may break down the blood brain barrier in humans, lead-ng to a cytokine mediated cell injury. Our objective was to determinehether the addition of magnesium sulfate (MgSO4) attenuates ac-

ivity of MMP9 in fetal cord plasma.TUDY DESIGN: We collected cord plasma in six normal, term, unla-ored patients. Using ELISA, we measured the activity of MMP9 with

arying concentrations of magnesium sulfate added in vitro. We ver-

Supplemen

fied our results by using a human umbilical cord vein endothelial cellHUVEC) line that was induced with a phorbol ester.ESULTS: Levels of endogenously active MMP9 in fetal cord bloodere approximately 10% of total MMP9. Addition of physiologicaloses of MgSO4 (0.07mg/ml) resulted in a 25% decrease in activeMP9 (p�0.03) in cord blood specimens (n�6). In a HUVEC line,

vernight incubation of MgSO4 resulted in a 32% decrease in MMP9ctivity (p�0.02).ONCLUSION: The addition of MgSO4, at concentrations found in theord blood of patients undergoing tocolysis, attenuated MMP9 activ-ty in fetal cord plasma.Similarly,MMP9 activity was also decreasedsing this dose of magnesium sulfate in the HUVEC line model.002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.616

451 Prediction of spontaneous preterm birthn asymptomatic triplet pregnancies usingetal fibronectin and cervical lengthathan Fox1, Daniel Saltzman2, Chad K. Klauser2, Danielleeress1, Donna Eckstein1, Andrei Rebarber2

Mount Sinai School of Medicine, New York, New York, 2Carnegieill Imaging for Women, New York, New YorkBJECTIVE: To evaluate fetal fibronectin (fFN) and cervical lengthCL) as predictors of preterm birth in triplet pregnancies.TUDY DESIGN: A historical cohort of 20 asymptomatic triplet preg-ancies with routine fFN and CL outpatient testing between 22-26eeks gestation were identified from a single MFM practice. Short CLas defined as 25mm. Mann-Whitney-U, Pearson correlation, Fish-

r’s exact test, one-way ANOVA and chi square for trend were usedhen appropriate.ESULTS: Three (15%) patients had a positive fFN. Compared to pa-ients with a negative fFN, patients with a positive fFN delivered atarlier gestational ages (Median GA 25.14 vs. 35.14, p�0.013), andad higher rates of SPTB �28 weeks (66.7% vs. 0%, p�0.016), �32eeks (100% vs. 11.8%, p�0.009), and �34 weeks (100% vs. 11.8%,�0.009). The CL measurement was significantly associated with ges-ational age at delivery (Pearson correlation � 0.517, p�0.020). Weompared outcomes in three groups: patients with a positive fFN andCL 25mm, patients with either test positive, and patients with both

ests negative (Table).ONCLUSION: In asymptomatic triplet pregnancies, fFN at 22-26 weeks

s a significant predictor of spontaneous preterm birth. The combina-ion of fFN and CL at 22-26 weeks outperforms either test alone.

utcomes in triplet pregnancies based on fFN and CL testing at 22-26 weeks

fFN negative andCL>25mm

Either fFN positiveor CL </� 25mm

fFN positive andCL </�25mm p

12 6 2.........................................................................................................................................................................................

ean GA atelivery

35.10 �/� 1.72 33.86 �/� 1.79 24.14 �/� 1.41 �0.001

.........................................................................................................................................................................................

Delivery28 weeks

0 0 100 0.001

.........................................................................................................................................................................................

Delivery32 weeks

8.3 33.3 100 0.009

.........................................................................................................................................................................................

Delivery34 weeks

8.3 33.3 100 0.009

.........................................................................................................................................................................................

002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.617

t to DECEMBER 2009 American Journal of Obstetrics & Gynecology S171