The role of prenatal Selective Serotonin Reuptake Inhibitor (SSRI) exposure and SLC6A4 promoter methylation status in shaping soothability at 3 and 6 months of age, for infants exposed to antidepressant medication prenatally (n = 46) and those not exposed (n = 69) was investigated. SSRI exposure status and duration of exposure (number of days) were examined along with neonatal methylation status at mean CpG 9,10 and via factor analysis across 10 CpG sites yielding PC1 (CpGs sites: 3,4,5,7) and PC2 (CpG 1,8). Analyses revealed interactions for methylation markers and SSRI exposure variables. A significant interaction between SSRI exposure and mean SLC6A4 methylation at CpG 9,10 and separately for PC1 emerged, controlling for multiple birth/medical and background covariates (e.g., Apgar scores, maternal education). Increased neonatal methylation status was associated with increased soothability changes from 3 to 6 months among infants prenatally exposed to SSRIs.

Prenatal exposure to maternal mood disturbances shapes children's cognitive development reflected in the critical construct of executive functions (EFs). Little is known, however, about underlying mechanisms. By examining cortisol responses in both everyday and lab challenge settings, we tested whether the child/offspring hypothalamic-pituitary-adrenal axis mediates effects of prenatal maternal mood on child EFs at age 6. In 107 Canadian children born to women with a wide range of anxious and depressive symptoms during pregnancy, we found that in boys but not girls, depressed and/or anxious prenatal maternal mood is associated with heightened diurnal cortisol levels in everyday settings, as well as heightened cortisol reactivity to a lab challenge and that this heightened reactivity was associated with poorer EFs. Among boys we also observed that cortisol reactivity but not diurnal cortisol mediated the association between depressed and/or anxious prenatal maternal mood and EFs. Depressed and/or anxious prenatal maternal mood was related to child EFs for both girls and boys. To our knowledge, this is the first study to demonstrate a mediating role for child stress regulation in the association between prenatal maternal stress-related mood disturbances and child EFs, providing evidence of a mechanism contributing to fetal programming of cognition.

In utero serotonin reuptake inhibitor (SRI) exposure is relatively common and neonatal behavioral outcomes vary greatly. Such exposure has led to questions about whether these effects refl ect an acute short-lived pharmacological phenomenon that results in a "withdrawal" condition, or sustained neurological changes associated with altered serotonin (5-HT) signaling that begins long before birth. Emerging reports now suggest that certain effects associated with in utero SRI exposure become evident during gestation. For instance, in utero SRI exposure appears to infl uence fetal brain blood fl ow and neurobehavior. In this chapter, we summarize current research evidence reporting the fetal effects of in utero SRI exposure. Given the paucity of empiric fetal data in humans, we draw from what we know about three postnatal fi ndings that may refl ect fetal developmental sequelae associated with in utero SRI exposure.