(HealthDay News) – Maternal mood and exposure to serotonin reuptake inhibitors (SRIs) in pregnancy affect development of the infant speech perception system, according to a study published online Oct. 8 in the Proceedings of the National Academy of Sciences.

Noting that SRI exposure during pregnancy alters neural plasticity, Whitney M Weikum, from the University of British Columbia in Vancouver, Canada, and colleagues examined their impact on infant language development, compared with exposure to maternal mood disturbances. Infants of depressed and SRI-treated mothers (SRI-exposed), non-SRI treated (depressed only), and non-SRI treated mothers with little or no depression (controls) underwent testing at 36 weeks of gestation while in utero on a consonant and vowel discrimination test. The infants also underwent a nonnative speech and visual language task at age 6 and 10 months.

The researchers found that, as expected, control infants were successful at 6 months and failed to discriminate language differences at 10 months, while SRI-exposed infants failed at 6 and 10 months and depressed-only infants failed at 6 months and performed the task successfully at 10 months. At 36 weeks of gestation, control fetuses responded to vowels but not consonant discrimination. In contrast, accelerated perceptual development was seen in SRI-exposed fetuses, who discriminated both vowels and consonants.

“Thus, prenatal depressed maternal mood and SRI exposure were found to shift developmental milestones bidirectionally on infant speech perception tasks,” the authors write. “By providing a deeper mechanistic understanding of how and when developmental trajectories are altered by early exposure to maternal mood disturbances and/or SRI exposure, more optimal outcomes can be realized for infants and their mothers.”

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