Unexpected intrauterine fetal death in parvovirus B19 fetal infection.

Parvovirus B19 infection during pregnancy can be transmitted to the fetus through the placenta. The consequences for the health of the fetus are very variable and can be very serious. They include intrauterine fetal death (IUFD) and miscarriage, which can lead to medico-forensic questions. For the most part, cases of IUFD take place during the second trimester of gestation and present an anatomopathologic picture characteristic of fetal infection with hydrops, placental edema, serous effusion, and erythroblastosis with nuclear inclusions. Endocardial fibroelastosis, medullar and thymic hypoplasia, and hepatic hemosiderosis are frequently present. In the third trimester, the cases are less frequent, not accompanied by hydrops, and can depend more on placental compromise than on direct infection of the fetus. We present 5 cases of IUFD resulting from parvovirus B19 and we discuss the pathogenetic and anatomopathologic aspects and obstetric liability. In 4 cases, the IUFD took place suddenly, in the absence of symptoms, in women who had not previously shown any symptom of the viral infection. In one case, the patient was hospitalized following an ultrasound diagnosis of fetal hydrops and IUFD took place 5 days after admission. Of these cases 3 were verified in the second trimester and 2 in the third trimester. Only the cases of the second trimester and one of the 2 cases of the third trimester presented the characteristic aspects of fetal infection. The other case of third trimester was characterized by placental involvement.