The relationship between maternal anxiety and cortisol during pregnancy and birth weight of chinese neonates

Background: To determine the relationship between maternal anxiety and cortisol values and birth weight at various stages of pregnancy. Methods: Two hundred sixteen pregnant Chinese women were assessed for anxiety and depression and had measurement of morning fasting serum cortisol. Women were assessed either in the first (71), second (72) or third (73) trimester. Birth weights of all children were recorded. Results: There were significant negative correlations between anxiety level and birth weight of - 0.507 (p < 0.01) and - 0.275 (p < 0.05) in trimesters 1and 2. In trimester 3 the negative relation between anxiety and birth weight of -.209 failed to reach significance (p = 0.070). There was no relation between depression and birth weight in any trimester (p > 0.5 for all). Maternal cortisol was significantly inversely related to birth weight in trimester 1 (r = - 0.322) and with borderline significance in trimester 2 (r = - 0.229). Anxiety score and maternal cortisol were significantly correlated in each trimester (r = 0.551, 0.650, 0.537). When both anxiety score and maternal cortisol were simultaneously included in multiple regression analyses only anxiety score remained significant. Conclusion: Whilst both maternal anxiety score and maternal cortisol are inversely related to birth weight the associations with anxiety score were more robust perhaps indicating the importance of mechanisms other than, or in addition to, maternal cortisol in mediating the effects of anxiety. The findings indicate the importance of measures to reduce maternal anxiety, particularly of a severe degree, at all stages of pregnancy.