Incidence and risk of primary cytomegalovirus infection among pregnant women in Benin City Nigeria

Background:  Primary cytomegalovirus infection in pregnancy remains a leading cause of congenital hearing loss and mental retardation worldwide. Most women acquired CMV infection horizontally from their infected children or younger children who were cross- infected at school or day care facilities. Over 90% of infected women are asymptomatic and serological screening of all pregnant women is still not universally acceptable. Objectives: the aim of this study was to determine the incidence and risk of primary CMV infection among urban women in Benin City, Nigeria. Materials and Methods:  Using a descriptive cross-sectional design, blood samples were collected from 800 pregnant women attending antenatal clinic at the University of Benin Teaching Hospital, and were analyzed for CMV-specific IgG and IgM antibodies using ELISA technique. Women with IgM positive results were further evaluated for primary CMV infection using IgG avidity test. Risk factors were identified using a structured questionnaire administered by the researchers. Information sought in the questionnaire included; age, occupation, husband’s occupation, marital status, gestational age, number of children, history of blood transfusion, HIV-status and child-care practices such as use of nursery/daycare services. Results: The overall prevalence of CMV infection was 97.0%. Ninety two percent had previous infection, 3.0% had recurrent infection (reactivation or re-infection), 2.0% had primary infection and 3.0% were seronegative. There was a significant relationship between primary infection and social class, parity and child-care practice. Conclusion: The incidence of primary CMV infection and the proportion of seronegative pregnant women at risk in our environment is a compelling reason for the introduction of CMV health education and voluntary routine screening for pregnant women as part of antenatal care to reduce the burden of congenital CMV infection. Keywords : Primary CMV Infection, Pregnancy, Risk factors, Nigeria.