To examine fine motor differences between preschoolers with prenatal exposure to serotonin reuptake inhibitor (SRI) and children of mothers with major depressive disorder.

A subset of children (N = 40) from a larger study on the effects of prenatal SRI and untreated major depressive disorder participated in a kinematic task of visual motor and fine motor functions at ages 4-5 years: exposure to SRI (n = 15), untreated major depressive disorder exposure (n = 10), and the control group (n = 15). The task was to reach and secure a peg, then drop it in a small hole near the start position in the light condition with full visibility or in the glow condition in which a phosphorescent peg glows in the dark. Movement-tracking software measured the positioning of the moving hand and fingers.

In the glow condition, the group exposed to SRIs had a greater proportion of maximum aperture than the group with major depressive disorder, and the group exposed to SRIs was slower than the group with major depressive disorder to drop the peg into the hole. In the glow condition, the trajectory of the group exposed to SRI was less straight than the group with major depressive disorder, and the group with major depressive disorder had a straighter trajectory than the control group.

This study provides evidence that preschool aged children with prenatal SRI exposure have poorer fine motor and visual-motor control compared with those with prenatal untreated major depressive disorder.