Frequency and significance of preterm delivery in twin pregnancies

Objective: We investigated the frequency of preterm delivery and its influence on the neonatal outcome in twin pregnancies at a perinatal center. Are there differences in the course of twin pregnancies with preterm or term delivery? Method: A retrospective investigation was carried out at the Department of Obstetrics on 502 twin pregnancies and deliveries between 1978 and 1993. Pregnancy history and clinical parameters were compared among preterm (< 37 + 0 weeks) and term deliveries. Result: Median duration of all twin pregnancies was 36 + 3 weeks of gestation. In the preterm group, preterm labor was more frequent, both, the first and the second neonate had lower birth weight and were more often admitted to the neonatal intensive care unit (NICU) where they stayed longer than full-term neonates needing intensive care. Perinatal deaths occurred only in the preterm group. Conclusions: The incidence of preterm delivery is significantly elevated in twin pregnancies and consequently the incidence of low- and very-low-birth-weight-infants and perinatal mortality. Preterm delivery is the main reason why twin pregnancies are at a higher risk for an adverse neonatal outcome and thereby cause considerable costs. (C) 2000 International Federation of Gynecology and Obstetrics.