Pregestational, periconceptional, and gestational primary maternal cytomegalovirus infection: prenatal diagnosis in 508 pregnancies.

OBJECTIVE The objective of the study was to evaluate the vertical transmission rate and fetal risk following primary maternal cytomegalovirus infection before and around conception. STUDY DESIGN Data of patients referred to fetal medicine clinic in 1 tertiary center in Israel were evaluated. Each included subject had primary maternal cytomegalovirus infection determined by serology, precise gestational dating, and testing of fetal infection. Subjects were assigned to five subgroups: pregestational, periconception, and first, second, or third trimester of pregnancy. RESULTS Five hundred eight pregnancies were included. None of the 97 pregnancies in the preconception group and 6 of the 130 periconception subjects (4.6%) were congenitally infected. Transmission rates were 34.8%, 42.0%, and 58.6% for the first, second, and third trimesters, respectively (P = .049). Prenatal and postnatal follow-up indicated that third-trimester infection has no clinical effect on the fetus. CONCLUSION Pre- and periconception maternal infection carries small risk for fetal infection, whereas it is positively correlated to time of maternal infection during pregnancy.