Objectives: To study the association between Epstein-Barr virus (EBV) antibody status in early pregnancy and pregnancy outcomes including fetal death, length of gestation and fetal weight and length at birth.
Design: Nested control study.
Setting: Population based health registers.
Population: The source population comprised 35,940 pregnant women. Cases were all (280) women with fetal death and a random sample of 940 women with a live born child.
Method: Information on pregnancy outcome was obtained from the Norwegian Medical Birth Registry. Serum samples from the first trimester were tested for EBV antibodies. In women seronegative for EBV, further serum from late pregnancy was analysed to detect seroconversion. Main outcome measures Vital status, length of gestation, weight and length at birth.
Results: There was no association between EBV antibody status and fetal death. Women with significant EBV reactivation had a significantly shorter duration of pregnancy, and associated lighter babies, compared with women without significant reactivation (stillborn: 176 vs 197 days, P=0.16, and live born: 271 vs 279 days, P=0.03, respectively).
Conclusion: Significant reactivation of EBV infection during pregnancy may influence pregnancy duration.