Screening and prenatal diagnosis of fetal cytomegalovirus infection: experience in a western Chinese city.

Objective: To explore the application value of serology testing and fetal ultrasound examination in screening for fetal cytomegalovirus(CMV) infection. To explore the application value of CMV polymerase chain reaction (PCR) in amnio fluids in prenatal diagnosis of fetal CMV infection.

Methods: This is a retrospective study performed at Chengdu Women's and Children's Central Hospital between 2021 and 2024. The baseline of preconception CMV infections and recent infections were investigated via serology testing. Pregnant women with suspicious serology for recent infection and/or ultrasound abnormalities suggestive of fetal infection underwent amniocentesis to obtain amniotic fluid for CMV PCR. The pregnancy outcomes of women with suspicious serology for recent infection and those who underwent amniocentesis were analyzed.

Results: The seroprevalence was 95.65%(55262/57778) and 0.99%(571/57778) for immunoglobulin G(IgG) and immunoglobulin M (IgM) antibodies respectively. Among the 315 pregnant women with positive IgM results who performed CMV IgG avidity index and/or dynamic IgM/ IgG tests, only 2.22%(7/315) confirmed recent infection and 2.54%(8/315) suspected recent infection: three terminated pregnancies including one with positive CMV PCR results and two with other reasons, and 12 gave birth to asymptomatic babies. 576 pregnant women with suspicious serology for recent infection and/or ultrasound abnormalities suggestive of fetal infection performed CMV PCR in amniotic fluid. Among them, we got 438 pregnancy outcomes, including 25 terminated pregnancies, eight stillbirths, and 405 live births. None of the 405 live births had symptoms related to CMV infection at birth, except two with mild hearing loss without known cause. Four fetal infections were diagnosed, including three who performed amniocentesis and CMV PCR and one accidentally diagnosed by copy number variation sequencing(CNV-seq). Three of them were negative for IgM in first-trimester screening.

Conclusions: Ultrasound screening plays a more important role than serology screening in areas with a high seroprevalence of CMV antibodies. Assays for both chromosome disorders and CMV PCR in amniotic fluids should be suggested to pregnant women with ultrasound abnormalities suggestive of fetal infection.