Quantifying the Burden of Congenital Cytomegalovirus Infection With Long-term Sequelae in Subsequent Pregnancies of Women Seronegative at Their First Pregnancy.

Background: In women seronegative before pregnancy, congenital cytomegalovirus (cCMV)-related sequelae are exclusively seen in those infected in the first trimester of pregnancy. Following a maternal primary infection in the first trimester, up to 30% of infected neonates suffer long-term sequelae. Maternal parity is an established risk factor of cCMV in previously seronegative women. Our objective was to quantify, in a population of women seronegative at their first pregnancy, the risk of cCMV and related sequelae following primary infections in the first trimester in subsequent pregnancies.

Methods: There were 739 women seronegative at their first pregnancy who had at least 1 of 971 subsequent pregnancies and deliveries managed at our institution. All women had CMV immunoglobin (Ig) G and IgM testing at 11-14 weeks of each pregnancy.

Results: Between 2 consecutive pregnancies, 15.6% (115/739) of women seroconverted. Of these seroconversions, 29% (33/115) occurred in the periconceptional period or in the first trimester. The risks for cCMV and related sequelae (neurologic and/or hearing loss) following a maternal infection in the first trimester were, respectively, 24- and 6-fold higher (risk ratios, 24 [95% confidence interval {CI}, 10.8-62.3] and 6 [95% CI 1.5-24], respectively) than in the general pregnant population. Of all primary maternal infections and fetal infections in the first trimester, 88% (29/33) and 92% (11/12), respectively, occurred when the inter-pregnancy interval was ≤2 years.

Conclusions: Women seronegative at their first pregnancy with a subsequent pregnancy within 2 years have the highest risk of delivering a child with cCMV-related sequelae. These women should be made aware of the risk and given the opportunity of serology screening in the first trimester.