ACARDIAC FETUS

Acardiac fetus is a rare lethal fetopathy usually encountered in monoz ygous pregnancies. Ultrasound prenatal diagnosis has enabled an increa sing number of observations and raised the need for an adequate therap eutic approach since the spontaneous prognosis for the healthy twin is unfavorable in half of the cases. An acardiac fetus was identified at 12 weeks gestation in a 36-year-old woman. Growth of the healthy fetu s was carefully monitored and progressed normally to delivery by cesar ean section of a 2.900 kg boy at 36 weeks. At delivery, the acardiac f etus was found to be totally free of any attachment, floating in the r emaining fluids. Pathology examination showed a 16 g macerated fetus w ith a cephalic extremity, a ventral pedicle and a syrenomelic caudal e xtremity. The caryotype was not significative. Acardiac fetus occurs i n less than 1% of multiple pregnancies and can develop in single pregn ancies. Twin reversed arterial perfusion has been recognized as necess ary for development of the perfused fetus. Genetic and immunologic the ories have been proposed to explain the pathogenesis which remains unk nown. Clinical management depends on the spontaneous development of th e acardiac fetus and the deleterious consequences for the healthy twin resulting from heart failure, anasarca or prematurity. Medical manage ment with digoxin, or selective extraction by hysterotomy may improve prognosis but results have been variable. Echoguided umbilical cord li gation has also been proposed to improve maternal mortality. Therapeut ic abstention is no longer indicated at prenatal diagnosis of an acard iac fetus and a healthy twin despite the risks of invasive treatment.