A rigorous new study examining the association between ultrasounds during the first or second trimester of pregnancy and later development of autism spectrum disorder, however, delivers some good news.

The study, which analyzed the medical records and ultrasound details of more than 400 kids who were born at Boston Medical Center, found there was no increase in the number of prenatal scans or duration of ultrasound exposure in children with autism compared with kids with typical development or separate developmental delays.