Ultrasound should not be done on pregnant women in their first trimester unless medically necessary.

A University of Washington researcher says a new autism study reinforces that federal recommendation.

Sara Webb, a UW associate professor of psychiatry and behavioral sciences, told KUOW’s Emily Fox that her team looked only at children with autism.

She said there was a problem for one group of kids who were exposed to ultrasound.

“Boys that had genetic errors who received an ultrasound during first trimester were more likely to have worse outcomes,” she said. “They were more likely to have more repetitive behaviors and lower IQ than those boys who didn’t have first trimester ultrasound.