Objectives: To evaluate the proportion of pregnant women agreeing to cytomegalovirus (CMV) serologic screening. To collect data on CMV infection during pregnancy.
Design: Prospective study.
Setting: During two years, all pregnant women were informed on CMV infection. If the patient agreed, serological testing was performed around 12 weeks of gestation (WG) and, if negative, redone around 36 WG.
Population: Four thousand two hundred and eighty-seven pregnant women followed from 12 weeks to delivery.
Methods: If the first CMV serologic test was negative, detailed hygiene information was given to the parents. Diagnosis of primary infection was based on the detection of CMV-G, CMV-M and low CMV-G avidity index. When maternal infection was confirmed, diagnosis of CMV congenital infection was done in the newborns by urine culture within the three days following birth. Crude infection-rate data consisted of the number of CMV infection cases and person-time units for both exposed to hygiene CMV information (12 to 36 WG) and unexposed pregnant women (first 12 WG).
Main outcome measures: Rate of CMV seropositive and seronegative women. Rate of women agreeing for screening. Rate of primary infection. Rate of seroconversion. Number of CMV-infected newborns.
Results: Among the 4287 women followed, 3792 were either seronegative or with an unknown immune status. 96.7% out of them agreed for screening. 53.2% were initially CMV-specific IgG negative. Primary infection was detected in nine women between 0 and 12 WG (0.46%) and seroconversion was diagnosed in five women between 12 and 36 WG (0.26%) (mid P = 0.02, 95% CI [1.07-13.6]).
Conclusions: If clear information on CMV infection during pregnancy is given, patients frequently agree to screening. The rate of seroconversion after information, observed in this study, is low after counselling.