Acardiac fetus complicating a triplet pregnancy: management and outcome

To report our experience with the management of triplet pregnancies complicated by an acardiac fetus.

During the 5-year period from 2003 to 2008, five cases were identified. The prenatal sonographic findings, antepartum course, antenatal intervention if performed, and perinatal outcome of each case were reviewed.

Four pregnancies were spontaneously conceived and one was achieved by in vitro fertilization. Three pregnancies were dichorionic and two were monochorionic, and two acardiac fetuses were part of a monoamniotic set. All cases underwent an early sonographic examination, but the diagnosis was only made in the first trimester in only two cases, as the acardiac fetus was overlooked or inaccurately identified as a dead fetus in the remaining three cases. Early fetal demise before 12 weeks occurred in a case of monochorionic-triamniotic triplets. Percutaneous laser coagulation of the main intra-abdominal vessel was attempted at 17 weeks in two cases, with subsequent delivery after 34 weeks and perinatal survival of three of the four structurally normal fetuses. In the other two pregnancies which were managed expectantly, both were complicated by severe preterm delivery with perinatal survival of three of the four structurally normal fetuses. Overall, there were no survivors in one case, one twin survived in two cases, and two twins survived in the remaining two cases. None of the survivor had neurological sequelae.

The presence of an acardiac fetus in a triplet pregnancy carries a high risk for poor pregnancy outcome, including fetal death and severe preterm labor. Prenatal intervention may be indicated in some cases, but does not prevent fetal death of the pump twin.