Incidence of intrauterine complications in monoamniotic twin gestation.

We compared the incidence of intrauterine complications, such as twin-twin transfusion syndrome, between monochorionic-monoamniotic (MM) and monochorionic-diamniotic (MD) twin gestations. We retrospectively evaluated a series of 11 MM and 211 MD twin gestations managed after 22 weeks' gestation at our hospitals. One MM twin gestation was diagnosed with twin-twin transfusion syndrome based on clinical presentation of polyhydramnios and hydrops. The incidence of twin-twin transfusion syndrome in MM twin gestations (9.1%) was not measurable different from that in the MD twin gestations (7.6%, p=0.09). There were no measurable differences in the incidence of other complications, such as growth discordance >25% or intrauterine fetal demise between the two groups. MM twin gestations should be kept under close management while carefully monitoring for any circulatory imbalance between the twins.