Objective: To describe the obstetric management and perinatal outcome of antenatally diagnosed monoamniotic twin pregnancies (MATP) in a tertiary level maternity unit.
Setting: Port-Royal Maternity Hospital, Paris, France.
Population: MATP that progressed beyond 22 weeks seen from 1993 to 2001.
Methods: A retrospective chart review of all twin pregnancies. Diagnosis of MATP was made by ultrasonography and confirmed by placental pathology.
Main outcome measure: Perinatal mortality.
Results: Among the 1242 twins pregnancies delivered during the study period, 19 were monoamniotic. Four fetuses (10% of all births) had malformations. Perinatal mortality was high (n= 12, 32%) because of fetal deaths (nine cases) and very preterm births (three neonatal deaths). No fetal deaths occurred after 29 weeks. Of the 15 women with at least one live fetus before labour, 6 gave birth by vaginal delivery (40%). No obstetric accidents occurred during vaginal deliveries.
Conclusion: Perinatal mortality of MATP is still very high, even with accurate, early antenatal diagnosis, intensified surveillance and delivery provided in a tertiary level hospital. The main causes of perinatal deaths are cord accidents in utero, congenital anomalies and very preterm births.