Infections during pregnancy may cause autism, study finds

A new study suggests that women infected with genital herpes during pregnancy are at a higher risk for having a child with autism.

Women who had active infections early in pregnancy were twice as likely to have a child with an autism spectrum disorder as women who did not, according to the researchers.

“We believe the mother’s immune response to HSV-2 (herpes simplex type 2) could be disrupting fetal central nervous system development, raising risk for autism,” Milada Mahic, a researcher at Columbia University who led the research team, told NBC News.

Researchers believe the woman’s immune response to the infection (the inflammation) may be causing the damage – not the virus itself.

The study tested women for immune responses to four viruses known to cause birth defects, including rubella, herpes simplex type 1 (cold sores) and herpes simplex type 2 (genital herpes).

Women with high levels of antibodies to genital herpes midway through their pregnancies were twice as likely to have a baby with autism. None of the other viruses seems to affect autism risk, according to the researchers.

Marissa Harshman

I'm the health reporter for The Columbian newspaper in Vancouver, Wash. I started at The Columbian -- my hometown newspaper -- in September 2009. Reach me at or 360-735-4546.