483: The relation between duration of rupture of membranes and perinatal outcome in patients with preterm delivery

Abstract

and perinatal outcome in patients with preterm delivery Jantien van der Heyden, Stijn van Teeffelen, David van der Ham, Jelle Schaaf, Anita Ravelli, Christine Willekes, Jan Nijhuis, Ben Mol VieCuri Medical Center, Department of Obstetrics and Gynaecology, Venlo, Netherlands, Maastricht University Medical Center, Obstetrics and Gynecology, Maastricht, Netherlands, Maastricht University Medical Center, Obstetrics & Gynecology, GROW School for Oncology and Developmental Biology, Maastricht, Netherlands, Academic Medical Center, Obstetrics and Gynecology, Amsterdam, Netherlands, Academic Medical Center, Medical Informatics, Amsterdam, Netherlands, Academic Medical Center, Department of Obstetrics and Gynaecology, Amsterdam, Netherlands OBJECTIVE: To assess the association between duration of rupture of membranes on perinatal outcome in patients with preterm delivery. STUDY DESIGN: We used data from the nationwide perinatal registry (PRN) from 1999 to 2007. We selected singleton pregnancies with preterm delivery between 26 0/7 and 36 6/7 weeks. We studied the association between duration of rupture of membranes (ROM) and perinatal outcome for different gestational ages. Perinatal outcome was defined as perinatal mortality, neonatal sepsis, Apgar score 7 after 5 minutes and composite morbidity (respiratory distress syndrome, necrotizing enterocolitis and intraventricular hemorrhage). RESULTS: During the study period, 166,118 births were complicated by preterm delivery between 26 0/7 and 36 6/7 weeks. The perinatal mortality rate in this group was 2.5%. For a gestational age between 26-30 weeks, the mortality rates for women delivering before and after 24 hours of ROM were 30% and 3.9% respectively (OR .34 (.22 to .55)). For gestational age groups at 30-33, 34, 35 and 36 weeks, these rates were 6.9% versus 0.9%, 2.6% versus 0.5%, 1.5% versus 0.4%, and 0.8% versus 0.4%, respectively (OR .21, .33, .32 and .36, all P .05). Sepsis rates were comparable with short and prolonged PPROM when PPROM occurred before 34 weeks (OR 1.1), but higher after prolonged PPROM when PPROM occurred after 34 weeks (OR 1.6, 1.9 and 2.6 for 34, 35 and 36 weeks, all P .05). The patterns of low Apgar score and composite morbidity resembled that of perinatal mortality. CONCLUSION: In women with a preterm delivery, prolonged duration of ROM is not associated with an increased risk of perinatal mortality, morbidity or low Apgar score at any gestational age. The risk of neonatal sepsis increases with longer duration of ROM in pregnancies over 34 weeks. These data do not support a policy of induction of labor in case of PPROM. 484 Ethnic disparities in spontaneouspreterm-birth-related perinatal mortality Jelle M. Schaaf, Ben Mol, Ameen Abu Hanna, Anita C.J. Ravelli Academic Medical Center, Medical Informatics, Amsterdam, Netherlands, Academic Medical Center, Department of Obstetrics and Gynaecology, Amsterdam, Netherlands OBJECTIVE: Although preterm birth has been defined as delivery before 37 weeks of gestation, ethnic disparities both in the risk of preterm birth as well as in the risk of perinatal mortality after preterm birth have been identified. We hypothesize that the definition of preterm birth should incorporate ethnicity, as normality could be different between women of different ethnic origins. To test this hypothesis, we studied ethnic disparities in spontaneous preterm birth and its subsequent mortality. STUDY DESIGN: We used data of the nationwide perinatal registry (PRN) of The Netherlands. For this study all singleton births between 1 January 1999 and 31 December 2007 were selected. We defined preterm birth as birth before 37 weeks. First, we studied the risk of preterm birth for Caucasians, Mediterraneans, Black women, SouthAsians and other Asian women. We then analysed mortality, defined as intrapartum or neonatal mortality within 28 days, in case of preterm birth in these ethnic groups. We chose 26 weeks as lower limit as there were active management differences between hospitals below this gestational age during the study period. We used multivariate logistic regression methods. RESULTS: We analyzed data of 969,491 women. Risk of delivery before 37 weeks was 5.3% in Caucasians, 4.7% in Mediterranean, 7.5% in Black women, 8.5% in South-Asians and 5.8% in other Asian women (Table 1). For the 50,823 women who experienced preterm birth between 26 and 37 weeks, the risks of perinatal mortality were 73, 65, 67, 67 and 67 respectively. The risk of mortality after preterm birth seems to be lower for all ethnic groups (when compared to Caucasians) and was significantly lower for Mediterranean women (odds 0.67). CONCLUSION: When preterm birth was defined as delivery before 37 weeks, both Black and South-Asian women had a significantly increased risk to deliver preterm. Since the subsequent risk of perinatal mortality after delivery before 37 weeks seems to be decreased in all ethnic groups as compared to Caucasian women, we plead for ethnic specific definitions for preterm delivery. Poster Session III Doppler Assessment, Fetus, Prematurity www.AJOG.org