Maternal SSRI Use During Pregnancy: Links Between Gut Microbiome, Offspring Behaviour, and Brain Transcriptomics.

Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed to treat maternal depression during pregnancy, yet their potential impact on foetal brain development remains a concern. Although maternal illness is a known confounder, growing evidence from both clinical and preclinical studies suggests that perinatal SSRI exposure may independently influence neurodevelopmental outcomes. This review draws on rodent studies to explore how developmental SSRI exposure affects the gut microbiome, maternal behaviour, myelination, and offspring social behaviour. Elevated serotonin levels caused by SSRIs can alter both brain development and the maternal gut microbiota, with possible long-term effects on offspring. Behaviourally, SSRI-exposed offspring often show reduced social play, altered social interactions, and sex-specific effects on aggression and sexual behaviour, in which males appear more sensitive to these effects than females. Maternal care is only modestly affected. Overall, developmental SSRI exposure in the absence of maternal illness can disrupt brain development and social behaviour in offspring, potentially through gut-brain axis mechanisms and altered myelination.