Fetal Malformations and Multiple Pregnancy - Revista Brasileira de Ginecologia e Obstetrícia

Purpose: to demonstrate the types of fetal malformations in multiple pregnancy and their relation to chorionicity. Methods: one hundred and sixty-nine multiple pregnancies were evaluated. In all cases prenatal ultrasound examination was performed during antenatal care. Chorionicity was defined by: first trimester ultrasound evaluation (absence of lambda sign); presence of two separate placentas; different fetal sex; pathological placental examination. Results: twenty-four (14.2%) fetal malformations were observed, 22 in twin and 2 in triplet pregnancy. In the group with fetal malformations 13 were monochorionic, 4 dichorionic and in 5 the chorionicity was unknown. Some malformations were unique to twins (conjoined twins n = 5, acardiac twin n = 3) and others were nonunique to twins. The gestational age at delivery was lower in the group with fetal malformations compared to the group without fetal malformations. Conclusion: the majority of malformations occurred in the monochorionic pregnancies. In multiple pregnancies early determination of chorionicity is helpful to establish the prognosis and to plan the management of pregnancy.