Perinatal mortality and mode of delivery in monochorionic diamniotic twin pregnancies ≥32 weeks of gestation: a multicentre retrospective cohort study

Objective To study perinatal mortality rates in a cohort of 465 monochorionic (MC) twins without twin-twin transfusion syndrome (TTS) born at 32 weeks of gestation or later since reported interauterine fetal death (IUFD) rates > 32 weeks of gestations in the literature vary, leading to varying recommendations on the optimal timing of delivery, and to investigate the relation between perinatal mortality and mode of delivery. Design Multicentre retrospective cohort study. Setting Ten perinatal referral centres in the Netherlands. Population All MC twin pregnancies without TTTS delivered at 32 weeks of gestation between January 2000 and December 2005. Methods The medical records of all MC twin pregnancies without TTTS delivered at the ten perinatal referral centres in the Netherlands between January 2000 and December 2005 were reviewed. Main outcome measures Perinatal mortality in relation to gestational age and mode of delivery at 32 weeks of gestation. Results After 32 weeks of gestation, five out of 930 fetuses died in utero and there were six neonatal deaths (6 per 1000 infants). In women who delivered 37 weeks, perinatal mortality was 7 per 1000 infants. Trial of labour was attempted in 376 women and was successful in 77%. There were three deaths in deliveries with a trial of labour (8 per 1000 deliveries), of which two were related to mode of delivery. Infants born by caesarean section without labour had an increased risk of neonatal morbidity and respiratory distress syndrome. Conclusions In MC twin pregnancies the incidence of intrauterine fetal death is low 32 weeks of gestation. Therefore, planned preterm delivery before 36 weeks does not seem to be justified. The risk of intrapartum death is also low, at least in tertiary centres.