Genetic amniocentesis in seventy twin pregnancies

Genetic amniocenteses were performed in 70 twin pregnancies over an 11-year period. Both sacs were successfully sampled in 49 of 62 patients (79%). The success rate was decreased (68%) with two placentas (anterior and posterior) and was improved with gestational age greater than or equal to 17 weeks (88%) and with ultrasound visualization of the septum (86%). Of three spontaneous abortions, two were attributed to amniocentesis (chorioamnionitis). When twin pregnancy is diagnosed in a patient with an indication for genetic amniocentesis, a careful reevaluation and discussion of risk factors with the couple are recommended.