Women taking antidepressants other than SSRIs during pregnancy have a heightened risk of developing gestational diabetes, an observational study shows.

The Canadian researchers say their study, involving more than 20,000 women with gestational diabetes (GDM), is the first to gauge risk from different classes of antidepressant and duration of use.

They found a 19% increased risk for use of any antidepressant in pregnancy compared with no antidepressant use, but noted that the potential for adverse outcomes needed to be weighed against the risk of depression relapse.

The greatest risk was found with the tricyclic amitriptyline (52% increased risk) and the SNRI venlafaxine (27%), but SSRIs were not associated with any significant increased risk.