Perinatal Outcome of Monoamniotic Twin Pregnancies

OBJECTIVE: To study perinatal mortality and neonatal morbidity in a large cohort of monoamniotic twin pregnancies with special emphasis to the gestational age-specific mortality. METHODS: The study included monoamniotic twin pregnancies delivered in 10 perinatal centers in the Netherlands between January 2000 and December 2007. RESULTS: A total of 98 monoamniotic pregnancies were included. The perinatal mortality rate (20 weeks of gestation through 28 days of life) was 19%; after exclusion of fetuses with lethal anomalies, the rate was 17%. After 32 weeks of gestation, only two pregnancies were complicated by perinatal mortality (4%). The incidence of twin-twin transfusion syndrome was 6%. The incidence of congenital heart anomalies and cerebral injury was 4% and 5%, respectively. CONCLUSION: The current incidence of perinatal mortality in monoamniotic twins is considerably lower than in previous decades, but it is still high and occurs throughout pregnancy.