West Nile Might Affect Pregnancy Outcomes

There is some evidence that infection with the West Nile virus (WNV) while a woman is pregnant can affect the baby. This has prompted the Centers for Disease Control (CDC) to recommend evaluation of such newborns for hearing defects and other abnormalities.

There is some evidence that infection with the West Nile virus (WNV) while a woman is pregnant can affect the baby. This has prompted the Centers for Disease Control (CDC) to recommend evaluation of such newborns for hearing defects and other abnormalities. “We are eager to have doctors report cases of mothers infected with WNV,” Dr. E. Hayes told Reuters Health. “The new guidelines will help us become more aware of pregnancies that are affected by WNV, and to help the medical community and the CDC better define what is happening in those situations.” In the CDC’s Morbidity and Mortality Weekly Report for February 27, Hayes and Dr. S. A. Rasmussen describe four cases of West Nile virus infection involving pregnant women during 2002. Three of the infants showed no evidence of infection or birth defects. The fourth infant was born at full term to a woman who had WNV brain infection during the 27th week of pregnancy. The baby was born with WNV infection, and had eye inflammation and areas of brain tissue destruction. “The cerebral destruction could be caused by a number of processes, but it’s possible that WNV could have caused it,” Hayes said. If WNV was responsible, there are probably other factors affecting outcome, he said. Comprehensive neonatal evaluations could help determine if these include factors that allow the virus to cross the placenta, or the mother’s virus level, or her immune response. The CDC is now gathering outcome data for pregnancies of WNV-infected mothers Until more is known, the CDC advises that babies born in this situation should be checked again at age 6 months for antibodies to the virus and hearing impairment. Pediatricians should document head circumference, physical characteristics and developmental milestones throughout the first year. (SOURCE: Morbidity and Mortality Weekly Report,Reuters Health, Feb 27, 2004)