Non-hydropic intrauterine fetal death more than 5 months after primary parvovirus B19 infection

Parvovirus B19 in pregnancy: possible consequences of vertical transmission

OBJECTIVE

The aim was to determine the outcome of pregnancies complicated by maternal Parvovirus B19 (B19) infection.

METHOD

Among 175 pregnant women referred to our clinic because of suspicion of a B19 infection, 63 with confirmed laboratory diagnosis of acute/recent B19 infection were followed up by ultrasound and Doppler measurement of the middle cerebral artery peak systolic velocity.

RESULTS

The vertical transmission rate was 31.7% (20/63). Of the 20 infected, 8 had hydrops, 1 had signs suggestive of meconium peritonitis and 1 had an isolated hydrothorax. Three fetuses presenting with hydrops were treated with intrauterine blood transfusion. Two of them died while the last showed resolution of anemia. Among the five untreated hydropic fetuses, one presented with mild signs that resolved spontaneously, two died at 16 and 17 weeks of gestation and two had also cardiomegaly and the parents opted for elective termination of pregnancy. All the anemic fetuses had middle cerebral artery peak systolic velocity values more than 1.8 multiples of the median. No stillbirth occurred.

CONCLUSIONS

The outcome of uncomplicated cases with B19 infection is good. In the presence of hydrops prognosis was very poor. It seems therefore logical to attempt to pick up this ominous signs early.

Diagnosis, management and possibilities to prevent parvovirus B19 infection in pregnancy

Human parvovirus B19 (B19V) infection in pregnancy can cause severe fetal anemia and nonimmune hydrops fetalis, which may be associated with spontaneous abortion and fetal death. Approximately 30–40% of women of child-bearing age are not immune to B19V infection. The risk to fetal life is particularly high if maternal infection occurs during the first 20 weeks of gestation. In this article we intend to give an overview on the molecular biology, epidemiology and management of B19V infection during pregnancy. These data will be combined with an assessment of the clinical situation of the infected fetus and the possibilities for avoiding and/or preventing B19V infection in pregnant women. Currently B19V infection is the causative agent of one of the most frequently occurring infectious complications in pregnancy that endangers fetal life, and so the necessity to develop a preventive vaccine is discussed.

Parvovirus B19 infection in human pregnancy

Human parvovirus B19 infection is widespread. Approximately 30-50% of pregnant women are nonimmune, and vertical transmission is common following maternal infection in pregnancy. Fetal infection may be associated with a normal outcome, but fetal death may also occur without ultrasound evidence of infectious sequelae. B19 infection should be considered in any case of nonimmune hydrops. Diagnosis is mainly through serology and polymerase chain reaction. Surveillance requires sequential ultrasound and Doppler screening for signs of fetal anaemia, heart failure and hydrops. Immunoglobulins, antiviral and vaccination are not yet available, but intrauterine transfusion in selected cases can be life saving.

Parvovirus B19 infection

Human parvovirus B19 (B19) is common in society. Among adults, more than 50% have contracted the infection and immunity is believed to last lifelong. Infection occurs in a few percent of pregnancies, and albeit rare it can then cause fetal anemia, non-immune fetal hydrops and fetal death. Among cases with fetal demise, B19 is found in significant numbers, especially in the second and third trimesters of pregnancy. There is no specific treatment or prophylaxis available against B19 infection, but counseling of non-immune mothers and active monitoring of confirmed maternal infections with intervention to correct fetal anemia is likely to decrease mortality. Passive immunization also has potential to resolve fetal complications, but needs further study.

Clinical aspects of parvovirus B19 infection

Parvovirus B19 is a significant human pathogen that causes a wide spectrum of clinical complications ranging from mild, self-limiting erythema infectiosum in immunocompetent children to lethal cytopenias in immunocompromised patients and intrauterine foetal death in primary infected pregnant women. The infection may also be persistent and can mimic or trigger autoimmune inflammatory disorders. Another important clinical aspect to consider is the risk of infection through B19-contaminated blood products. Recent advances in diagnosis and pathogenesis, new insights in the cellular immune response and newly discovered genotypes of human parvoviruses form a platform for the development of modern therapeutic and prophylactic alternatives.