Maternal antibodies against cytomegalovirus in pregnancy and the risk of fetal death and low birth weight

Background. The aim of this study was to assess the impact of maternal cytomegalovirus (CMV) antibody status in pregnancy on the risk of fetal death and of low birth weight. Methods. The study of fetal death risk was a nested case-control study. Cases were all women within a cohort of 35 940 pregnant women in Norway 1992-94, who experienced fetal death after 16th week of gestation (n = 281). Controls were 957 randomly selected women with live born children. Both groups were identified through linkage to the Norwegian Medical Birth Registry. The risk of low birth weight was studied in the live born children Results. Seventy-two percent (203/281) of the cases and 69% (662/957) of the controls had CMV immunoglobulin G (IgG) antibodies in the first trimester (P = 0.3). 0.4% (1/281) of the cases and 0.7% (7/957) had CMV IgM antibodies in the first trimester (P = 0.7). Among 322 initially CMV antibody-negative women, 11% (6/55) of the cases and 9% (24/267) of the controls had occurrence of CMV IgG and/or IgM antibodies (P = 0.7) during pregnancy. Also, after control for maternal age, parity, and follow-up time, no association between CMV antibodies and fetal death was found. CMV antibody status was not associated with low birth weight. Conclusions. This study does not support a causal relation between CMV infection in pregnancy and fetal death or low birth weight.