From the New York Times:

A cautiously worded study based on data collected in Sweden has found that “in utero exposure to both selective serotonin reuptake inhibitors (S.S.R.I.’s) and nonselective monoamine reuptake inhibitors (tricyclic antidepressants) was associated with an increased risk of autism spectrum disorders, particularly without intellectual disability.”

The Swedish medical birth register, which contains data on current drug use reported by mothers early in their pregnancies, along with a system of publicly funded screenings for autism spectrum disorders and extensive national and regional registers of various health details, makes a detailed, case-control study possible — one that controls for other variables like family income, parent educational level, maternal and paternal age and even maternal region of birth (all factors the authors note have been previously associated with autism).

This is the second study in two years to associate antidepressant use during pregnancy with an increased incidence of autism in exposed children. An earlier, smaller study in California also found a modest increase in risk. The Sweden-based study could not exclude the possibility that it was the severe depression, rather than the use of antidepressants, that created the association, but the smaller California study (which considered only S.S.R.I.’s) found “no increase in risk” for mothers with a history of mental health treatment in the absence of prenatal exposure to S.S.R.I.’s.