Maternal herpes labialis in pregnancy and neural tube defects.

According to previous case reports, some congenital abnormalities (CAs) of the brain, such as microcephaly, are a result of intrauterine herpes simplex virus infection. A population-based case-control study was conducted to determine the risk of neural tube defects (NTDs) after maternal herpes labialis infection during pregnancy. Data were taken from the Hungarian Case-Control Surveillance of Congenital Abnormalities from 1980 to 1996, which included 1202 children with NTDs and 21641 comparison children with CAs other than NTDs. The adjusted relative risks (odds ratio [OR]) for NTDs associated with maternal herpes labialis in the first trimester of pregnancy was OR 1.19 (95% confidence interval [CI] 0.68-2.06), and in the entire pregnancy was OR 0.94 (95% CI 0.61-1.44). Self-reported maternal herpes labialis during pregnancy was not associated with a substantially increased risk of NTDs in infants.