[Obstetric and ethical-legal problems in a twin pregnancy with anencephalus and polyhydramnios of the leading twin beyond the 28th week of pregnancy].

Malformations are found twice as often in twins than in singletons. In the following case, we report on a twin pregnancy with anencephaly and polyhydramnion of the leading twin I, which was first diagnosed after 28 weeks of pregnancy. The foetal disease of twin I led to an appreciable dyspnoea of the mother that exacerbated to an incipient respiratory failure by the thirty-second week of pregnancy. The projected termination of pregnancy by Caesarean section based on a maternal indication was not performed, but instead a selective foetocide of the diseased twin. The live twin was delivered spontaneously without complications after thirty-eight weeks of pregnancy. The obstetric and legal ethical problems are discussed.