West Nile virus during pregnancy: a case study of early second trimester maternal infection.

A woman who contracted West Nile virus (WNV) neuroinvasive illness during her second trimester subsequently elected to terminate her pregnancy due to concerns of possible adverse effects of WNV on her developing fetus. Consent was obtained to test maternal and post-mortem fetal tissues for WNV infection. Fetal blood, liver, kidneys, spleen, umbilicus and amniotic fluid were negative for WNV RNA by polymerase chain reaction and negative for WNV IgM antibodies by ELISA, indicating that in this case there was no evidence of WNV transmission to the fetus. Until further information regarding outcomes of WNV infection during pregnancy is available, pregnant women in areas where WNV is transmitted should take precautions to avoid mosquito bites. Women with WNV illness during pregnancy should undergo regular prenatal checkups including ultrasound examinations to assess fetal development, and healthcare providers should promptly report cases of WNV in pregnant women to their state or local health department or to CDC. Copyright 2006 S. Karger AG, Basel.