Prenatal antidepressant exposure and longitudinal differences in body mass index up to 8 years of age in the offspring born to mothers with pre-pregnancy depressive and/or anxiety in the Norwegian Mother, Father and Child Cohort Study

ImportanceNo study with available data from birth into late childhood has explored how prenatal antidepressant exposure affects offspring body mass index (BMI) throughout childhood. ObjectiveTo determine the association between prenatal antidepressant exposure and longitudinal differences in child BMI up to age 8 years. Design, Setting, and ParticipantsWe used data from the Norwegian Mother, Father, and Child Cohort Study (MoBa) linked to the Medical Birth Registry of Norway and the MoBa Genetics. We included 6,084 pregnancy-child dyads (singleton, liveborn) with available parent-reported data on child BMI from birth up to 8 years of age, born to women with depression/anxiety prior to pregnancy. Analysis was performed between January 2023 and April 2024. ExposuresPrenatal antidepressant exposure was categorized as i) continued antidepressants in pregnancy (n=626); ii) discontinued antidepressants proximal to pregnancy (n=412); or iii) unexposed to antidepressants both before and during pregnancy (n=5,046). Main outcomes and measuresChild BMI up to 8 years of age. Mean BMI differences over time across antidepressant exposure groups were compared using multilevel mixed-effect linear models. ResultsChildren born to mothers who continued antidepressant into pregnancy had comparable childhood BMIs with those born to unexposed mothers or mothers who discontinued antidepressant proximal to pregnancy. Higher BMI was observed up to 3 years of age among male offspring born to antidepressant continuers compared to discontinuers, especially in those exposed to selective-serotonin-reuptake-inhibitor before pregnancy (mean difference in BMI, {beta}=0.334; 95% CI: 0.081 to 0.588 at baseline). Lower BMI was seen among female offspring born to continued vs. discontinued mothers and the gap became larger over time, especially between low-moderate use of antidepressant vs. discontinuation during pregnancy. Analyses integrating parental genetic liability for depression, BMI, and antidepressant response using polygenic risk scores in a sub-population (n=1,913) suggests potential influence of the genetic component on the differences in BMI across antidepressant trajectory groups in some strata. Conclusion and relevanceThe longitudinal childhood BMI of children born to mothers with pre-pregnancy depression/anxiety did not differ across prenatal antidepressant exposure trajectories. Exploratory analyses revealed differences at specific time frames which might be sex-specific and potentially influenced by genetic liability profiles. KEY POINTSO_ST_ABSQuestionC_ST_ABSDoes prenatal antidepressant exposure affect longitudinal childhood BMI? FindingsIn this cohort study of 6084 pregnancy-child dyads in mothers with pre-pregnancy depressive/anxiety disorders, no difference in longitudinal childhood BMI across prenatal antidepressant exposure groups were observed. Exploratory analyses revealed differences at specific time frames which might be sex-specific and potentially influenced by parental genetic liability profiles. MeaningLongitudinal BMI throughout childhood of children born to mothers with pre-pregnancy depression/anxiety did not differ across prenatal antidepressant exposure trajectories. Further research is needed to investigate the time-dependent, sex-specific, and genetic-related aspects of some strata of antidepressant exposure on BMI differences.