If Epstein-Barr virus (or EBV) - the bug responsible for mononucleosis, among other ills - is reactivated during pregnancy, it may lead to early labor or even stillbirth, according to a new report.

“EBV reactivation in the first part of pregnancy was associated with shorter duration of pregnancy and lighter babies,” Dr. Anne Eskild from the Norwegian Institute of Public Health, Oslo, told Reuters Health. “Though not significant, this association was most prominent in stillborn children.”

Eskild and her colleagues investigated the risk of fetal death and other pregnancy outcomes according to EBV status during pregnancy, using the Medical Birth Registry of Norway. The team looked into 280 fetal deaths and 940 randomly selected live-born infants from among 35,940 pregnancies in the registry.

A first instance of EBV infection was seen in 1.5 percent of the pregnant women, the team reports in BJOG: An International Journal of Obstetrics and Gynaecology, and 25 percent of the women had signs of EBV reactivation during the first trimester.

The pregnancies of women with significant EBV reactivation were significantly shorter than those of women without reactivation, the report indicates.

Also, the rate of EBV reactivation was more than twice as high among women who delivered before 21 weeks (all of the infants were stillborn) than among women who delivered after 21 weeks (stillborn or live born), the researchers note.

EBV reactivation was also associated with lower average birthweight, body length and head circumference.

“Our findings need to be verified by others,” Eskild said, adding: “There is insufficient knowledge about the consequences of maternal EBV infection in pregnancy to make any clinical recommendations and guidelines.”

SOURCE: BJOG, December 2005.