Effect of birth order on respiratory distress syndrome in preterm twin pregnancy / 대한산부인과학회지

ABSTRACT

OBJECTIVES: To determine the effect of birth order on development of respiratory distress syndrome (RDS) in twin pregnancy according to the cause of preterm birth. METHODS: A retrospective analysis of 163 live born twin pairs who delivered at 24-34 weeks of gestation from January 1997 to April 2005 was done. Intrauterine fetal deaths or cases with severe fetal malformations were excluded. Subjects were categorized into three groups according to the cause of preterm birth a preterm labor (PTL) group, a preterm premature rupture of membrane (PPROM) group and other maternal-fetal indication group. One hundred forty four twin pairs (88.3%) were delivered by cesarean delivery. We analyzed the incidence of RDS and other morbidities such as bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis and early neonatal sepsis in above three groups. Each second-twin was compared for specific outcomes directly with its first-twin birth mate. RESULTS: Overall, the first-born twin had less RDS compared to the second-born twin (p=0.02). Specifically, a reduced incidence of RDS of the first-born twin was significant in the PPROM group, regardless of neonatal sex (p=0.001). In other groups, there was no correlation between birth order and RDS. Except for RDS in the PPROM group, neonatal mortality and other morbidities were not significantly different between the first- and second-born twins. CONCLUSIONS: There is a significant decreased risk of RDS in the first-born twins from PPROM, but not from PTL or other indications.