BackgroundEvidence exists that maternal antenatal depression may have adverse impacts on perinatal outcomes. However, the results of those studies are inconsistent and mainly focus on maternal depressive symptoms in the second or third trimester. MethodsThis prospective cohort study used a sub-sample of participants from the Sino-Canadian Healthy Life Trajectories Initiative trial. The Edinburgh Postnatal Depression Scale (EPDS) was used to screen for depressive symptoms in the first, second, and third trimesters, respectively. Infant growth indicator measurements were conducted in the first year of life. Logistic regression, Spearman correlation analyses and Generalized estimation equation (GEE) models were used to test the hypotheses. Results2,053 participants were recruited in this study, 326 of whom had at least one EPDS score ≥ 10 during pregnancy. A higher EPDS score in the first (aOR=1.053, 95% CI: 1.004-1.103) or in the second trimester (aOR=1.060, 95% CI: 1.007-1.115) was associated with greater risk of macrosomia. A higher EPDS score in the third trimester was associated with higher risks of preterm birth (aOR=1.079, 95% CI: 1.006-1.157) and the infant being small for gestational age (aOR=1.097, 95% CI: 1.015-1.185). GEE models showed that a greater EPDS score in the third trimester was associated with higher infant subscapular skinfold thickness (adjusted β=0.026, 95% CI: 0.003-0.050). ConclusionMaternal depressive symptoms in different trimesters were differentially associated with infant weight and growth parameters at birth and postnatally. The present study further highlights the importance of depression screening in all trimesters of pregnancy, including the first trimester.