Cognitive Outcomes of Children Exposed to Selective Serotonin Reuptake Inhibitors Through Breast Milk.

Importance: The cognitive performance of children prenatally exposed to selective serotonin reuptake inhibitors (SSRIs) has in some studies been shown to be reduced compared with that of unexposed children, potentially by factors associated with the underlying maternal disorder. However, cognitive performance following exposure to SSRIs through breastfeeding has not been previously studied. Objective: To determine whether the cognitive performance of children exposed to SSRIs both during pregnancy and breastfeeding differs from that of children with SSRI exposure limited to pregnancy. Design, Setting, and Participants: This prospective cohort study included the offspring of pregnant women enrolled in the MotherToBaby California cohort from May 8, 1989, to April 14, 2008. Children whose mothers were treated with SSRIs during pregnancy completed neurodevelopmental testing at 4 to 5 years of age (April 30, 1996, to August 12, 2012). Data were analyzed from January 10 to May 16, 2025. Exposures: Children exposed to SSRIs during breastfeeding were compared with breastfed children not exposed to SSRIs during breastfeeding and nonbreastfed children. Main Outcomes and Measures: Full-scale, verbal, and performance IQ were measured with the Wechsler Scales of Preschool and Primary Intelligence and compared using analysis of covariance adjusted for child sex, prematurity, and age at testing. Results: The sample included 97 mother-child dyads. Of the 97 children, 52 (53.6%) were female and 45 (46.4%) were male, with a mean (SD) age at testing of 4.9 (0.7) years. Of these, 22 children (22.7%) were exposed to SSRIs during breastfeeding; 37 (38.1%) were breastfed without SSRI exposure; and 38 (39.2%) were not breastfed. There were no significant differences in any adjusted mean IQ scores between breastfed children with and without postnatal SSRI exposure. Compared with nonbreastfed children, breastfed children exposed to SSRIs postnatally had significantly higher adjusted mean full-scale IQ scores (109.4 [95% CI, 104.5-114.4] vs 103.1 [95% CI, 99.3-106.9]; P = .046) and performance IQ scores (112.3 [95% CI, 106.7-118.0] vs 104.2 [95% CI, 99.9-108.5]; P = .03), but these differences were no longer significant after adjustment for factors related to the maternal mood during pregnancy. Conclusions and Relevance: In this cohort study including children prenatally exposed to SSRIs, additional exposure to SSRIs through breastfeeding was not associated with reduced IQ scores. Although measures of performance other than IQ were not evaluated, these findings suggest that breastfeeding can be encouraged during treatment with SSRIs.