Using large data sets, researchers determined children on the autism spectrum can be broken into three subgroups based upon co-occurring conditions, and those subgroups are associated with different prenatal risk factors. Infections, anti-inflammatory and other complex medications were associated with one group, while joint disorders and immune system problems were associated with another. The third subgroup was associated with overall pregnancy complications. Researchers have developed a new blood test that can for autism and prenatal risk factors for ASD.