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487 Risk factors for preterm prematureupture of membranes in twins

Jennifer Jolley1, Robert Ehsanipoor1,ichael Haydon2, David Lagrew3

1University of California, Irvine, Orange, CA, 2Long Beachemorial Medical Center, Long Beach, CA, 3Saddlebackemorial Medical Center, Laguna Hills, CA

OBJECTIVE: To describe risk factors for preterm premature rupture ofembranes (PPROM) in twin gestations.

STUDY DESIGN: Retrospective collection of chart data from twin preg-nancies delivered at two institutions between January 1998-December2005. Data abstracted included maternal demographics, antepartumcomplications, and delivery details. Relative risk (RR) for PPROMwith 95% confidence interval (CI) was calculated for multiple patientand pregnancy characteristics.RESULTS: A total of 904 subjects were evaluated. Of these, 108/90411.9%) patients experienced PPROM, 94 with dichorionic placenta-

S196 American Journal of Obstetrics & Gynecology Supplement to JANUARY 2

difference in gestational age at delivery between patients with PPROMand those without (33.2 weeks vs. 36.4 weeks, p��.0001). Age � 35years, tobacco smoking, and history of cervical surgery were not as-sociated with PPROM. Monochorionic twins were no more likely tohave PPROM than dichorionic twins (RR 0.84, 95% CI 0.49-1.42),and pregnancies conceived via assisted reproductive technology wereno more likely to have PPROM than spontaneous twins (RR 1.36,95% CI 0.95-1.96). Nulliparous patients were more likely to experi-ence PPROM than parous women (RR 1.88, 95% CI 1.27-2.77). Priorpreterm birth was a risk factor for PPROM (RR 2.26, 95% CI 1.04-4.90), as was antepartum bleeding (RR 2.74, 95% CI 1.38-5.44).CONCLUSIONS: Nulliparity, prior preterm birth, and antepartum

leeding were risk factors for PPROM in twin gestations.

488 Fetal lung maturity testing: predictionf overall neonatal outcomes?

Jeroen Vanderhoeven1, Suzanne Peterson1, Elizabethenpenny1, Dennis Mayock1, Hilary Gammill1

1University of Washington, Seattle, WAOBJECTIVE: We sought to evaluate the relationship between FLM test-ng and neonatal outcomes. We hypothesize that FLM studies are notssociated with non-respiratory complications.

STUDY DESIGN: We conducted a retrospective cohort study includingwomen with singleton pregnancies undergoing amniocentesis forFLM testing prior to delivery at the University of Washington betweenJanuary 1, 2006 and December 31, 2006. Detailed maternal and neo-natal variables were collected through chart abstraction. Chi square orFisher’s exact analysis was used to evaluate associations between FLMtesting and neonatal outcomes.RESULTS: Of 137 subjects, 24 were complicated by fetal anomalies, andn additional 3 FLM samples were collected vaginally, leaving 110 fornalysis. All FLM tests were performed by fluorescence polarization.he mean gestational age at FLM testing was 36.7 weeks and the mean

ime from FLM to delivery was 2.9 days. The FLM test indicated im-ature or transitional status in 29 (26%) and fetal maturity in 81

74%). FLM testing was associated with adverse respiratory outcomes1% in the mature group vs. 21% in the immature/transitional group,�0.001). Other adverse outcomes resulting in a change in clinicalanagement were evaluated. Jaundice was common in both groups

49% in the mature group vs. 70% in the immature/transitionalroup, p�0.07). Feeding difficulties were common as well and wereot associated with FLM testing (23% feeding difficulties in the ma-

ure group vs. 24% in the immature/transitional group, p�0.94).CONCLUSIONS: In this population of late preterm and early term deliv-ries, adverse neonatal outcomes not related to fetal lung maturationccurred commonly and were not predicted by FLM testing.

489 Neonatal outcome of late-preterm birthn twin pregnancy according to chorionicity

Ji-Hee Sung1, Hyun-Hwa Cha1, Mi-Young Shin1, Katerinaok Song1, Suk-Joo Choi1, Soo-young Oh1,heong-Rae Roh1, Jong-Hwa Kim1

1Samsung Medical Center, Sungkyunkwanniversity School of Medicine, Seoul

OBJECTIVE: To investigate the neonatal outcome in twin pregnancieselivered at late-preterm versus term and to evaluate whether theutcome is different between monochorionic (MC) or dichorionicDC) twins.

STUDY DESIGN: We retrospectively analyzed obstetric and neonataloutcome in twin pregnancies delivered beyond 34 weeks of gestationfrom October, 1994 to May, 2010. Subjects were categorized into twogroups; 1) twins born at 34-36 weeks’ gestation (late-preterm group)and 2) twins born beyond 37 weeks’ gestation (term group). Subjectsin each group were subcategorized into MC or DC twins. Pregnanciescomplicated by twin-to-twin transfusion syndrome, monoamniotictwin, one or more fetal death in utero and fetal chromosomal or non-

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