Transplacental Infection: Frequency, Testing, and Treatment

Infections transmitted through the placenta are caused by viruses [e.g., cytomegalovirus (CMV) and parvovirus B19 (B19V)], bacteria (e.g., Treponema pallidum spp. pallidum), and protozoa (e.g., Toxoplasma gondii). These infections may have serious consequences for the unborn child. In this article, we discuss current aspects of prevention, testing, and treatment.

This narrative review is based on pertinent publications (1946-1015) retrieved by a selective search in the PubMed/MEDLINE, Cochrane Library, ClinicalTrials.gov, and Google Scholar databases, along with the guidelines of medical societies.

The current incidence of transplacental infection in Germany is ca. 1 : 200 (CMV) to 1 : 500 000 neonates (syphilis). The diagnosis is made by the serological demonstration of antibodies. Before the 20^th week of gestation, the rate of vertical transmission is lower, but the potential for permanent harm is markedly higher than in the second half of pregnancy. 5-50% of transplacental infections lead to miscarriage or premature birth. Most infected fetuses are asymptomatic at birth, but there is still a 7-14% risk of sensorineural hearing loss from CMV and a 10-30% risk of retinochoroiditis from toxoplasmosis. Up to 60% of symptomatic neonates have long-term neurocognitive sequelae. Anti-infectious treatment is therefore indicated.

The most important preventive measures are hygiene education for pregnant women and prophylaxis against exposure. Anti-infectious treatment of pregnant women can reduce the risk of transmission, and the treatment of symptomatic neonates can improve the outcome.