Key Point: Study of 755 children with and without ASD shows possible 2nd trimester link.

Antenatal Ultrasound and Risk of Autism Spectrum Disorders


Grether JK, Li SX, Yoshida CK, Croen LA. Journal of Autism Development Disorders. 2010; 40(2):238 -245.

Comment by webmaster: The abstract does not reference these statements within the report but does call for further analysis:
“..increased risk of ASD was observed with increasing numbers of U/S examinations for… females in the 2nd trimester.” And, “This finding cannot be attributed to one or two outliers but could represent a chance finding.”


We evaluated antenatal ultrasound exposure as a risk factor for autism spectrum disorders (ASD), comparing affected singleton children and control children born 1995-1999 and enrolled in the Kaiser Permanente health care system. Among children with ASD (n=362) and controls (n=393), 13% had no antenatal exposure to ultrasound examinations; case-control differences in number of exposures during the entire gestation or by trimester were small and not statistically significant. In analyses adjusted for covariates, cases were generally similar to controls with regard to the number of ultrasound scans throughout gestation and during each trimester. This study indicates that antenatal ultrasound is unlikely to increase the risk of ASD, although studies examining ASD subgroups remain to be conducted.