Fetal blood sampling in twin pregnancies. Prenatal diagnosis and management of 19 cases

Twin pregnancies pose particular problems in both prenatal diagnosis and obstetric management. We present 19 twin pregnancies that underwent fetal blood sampling (FBS). The indications were mostly similar to those for singleton pregnancies, with both fetuses being sampled. There was one indication specific to twin pregnancies; disseminated intravascular coagulation in the retained twin after the death-in-utero (DIU) of the other. In 5 cases, only 1 twin was sampled; in 2 because the second twin was female in the diagnosis of an X-linked disorder; in 1 because of technical failure, and in 2 the other twin had predeceased. Eight pregnancies continued after the FBS delivering 2 live, healthy infants, though 5 were delivered before 37 weeks of gestation. In 7 cases there was a discordance in the diagnosis between the twins. In 3 of these cases the affected fetus underwent selective termination by air embolism; in 2 cases the pregnancies were continued and the affected twin not resuscitated; 1 pregnancy is still in progress, and 1 patient had a non-medically supervised termination of both twins in another country. Two patients miscarried within a week of the FBS. Two patients had only 1 living twin at the time of FBS; 1 had a second DIU a month after the FBS and the other a neonatal death at 11 days of age in an infant with severe porencephaly. FBS is technically feasible for similar indications as for singleton pregnancies though discordance in diagnosis raises specific management problems.