Pre-pregnancy overweight or obesity moderates the association between prenatal maternal depression and infant cord blood omega-3 levels

Background Empirical evidence has demonstrated associations between pre-pregnancy obesity and perinatal maternal depressive symptoms. Omega-3 is an essential fatty acid derived from dietary sources that is critical for fetal brain development. Pre-pregnancy obesity is associated with higher omega-3 intake, but a weaker association between dietary intake and respective maternal and cord blood omega-3 levels. Further, lower intake of omega-3 during pregnancy has been linked to higher depressive symptoms. Yet, prior studies have not examined the interactive effects of pre-pregnancy overweight or obesity (OWOB) and prenatal maternal depression on infant cord blood omega-3 levels. Methods Participants included 394 maternal-infant dyads from the NIH Environmental influences on Child Health Outcomes (ECHO) - Safe Passage Study in South Dakota. A pre-pregnancy body mass index > 25 was used to dichotomize participants as OWOB (54%) vs. non-OWOB (46%). Prenatal maternal depressive symptoms were measured using the Edinburgh Postnatal Depression Scale (EPDS) and prenatal maternal anxiety symptoms were measured using the State-Trait Anxiety Inventory (STAI). We implemented linear regression models to examine the interaction term between pre-pregnancy OWOB and prenatal maternal depressive symptoms on cord blood omega-3 levels controlling for preterm birth. Secondary analyses were stratified by pre-pregnancy OWOB status. Results We observed a significant interaction between pre-pregnancy OWOB and prenatal maternal depressive symptoms with cord blood omega-3 (F (4,379) = 6.21, p < .0001, adj. R ²  = 0.05). Stratified models revealed that only among individuals with pre-pregnancy OWOB, there was an association between prenatal maternal depressive symptoms with lower cord blood omega-3 levels (β = -0.06, 95% CI = -0.11, -0.02; F (2,208) = 4.00, p < .05, adj R ²  = 0.03). No associations were observed among non-OWOB participants. Conclusions Findings suggest maternal-placental transfer of omega-3 may represent one pathway by which maternal metabolic and mental health impacts infant development.