Congenital cytomegalovirus infection following primary maternal infection in the third trimester

Objective To determine the effect of primary cytomegalovirus (CMV) infection in the third trimester on fetal outcome. Design Observational study. Setting Four perinatal departments in tertiary hospitals in Israel. Population Twenty-eight women with primary CMV infection acquired after 25 weeks of gestation. Methods Prenatal evaluation included amniocentesis and ultrasonographic examinations. Maternal infection was determined from seroconversion and presence of low avidity anti-CMV immunoglobulin G after 25 weeks of gestation. Fetal CMV infection was diagnosed from CMV isolated or CMV DNA amplified from the amniotic fluid. Neonatal infection was established from CMV presence in their urine or anti-CMV IgM was in their peripheral blood immediately after birth. All liveborn neonates underwent cerebral ultrasonography, hearing assessment, and psychomotor development evaluation. Infected neonates were followed up for a median of 36 months (range 6-36 months). Main outcome measures Intrauterine CMV infection and neonatal CMV disease throughout follow up. Results Vertical transmission of CMV was documented in 21 (75%) of the 28 pregnancies. None of the 20 live infected newborn had symptomatic congenital infection. One pregnancy was terminated at 34 weeks following evidence of prenatal infection. Most of the patients (75%) had CMV serology test due to clinical signs of CMV disease. Conclusions Although CMV infection during the third trimester of pregnancy is highly transmissible, sequelae were not found among infected offspring.