Association of high cortisol levels in pregnancy and poor postpartum mental health and altered fetal growth. Analysis in the MAASTHI cohort study, Bengaluru

Background: The role of maternal stress levels on mothers’ mental health and fetal growth has been previously studied. We aim to investigate the association of serum cortisol level in pregnancy with birth outcomes and postpartum depressive symptoms in a public health facility, India. Methods: The current study is a part of the MAASTHI prospective cohort that assessed the relationship between maternal psychosocial environment and adverse neonatal outcomes and maternal mental health after birth. We assessed serum cortisol levels in stored blood samples in 230 pregnant women as a biomarker for stress during pregnancy. Pregnant women between 18 and 45 years of age, presenting at ≥ 14 weeks of gestation and providing voluntary written informed consent were recruited in the study. The Edinburgh Postnatal Depression Scale was used to assess postpartum depressive symptoms and detailed infant anthropometric measurements were carried out at birth. Results: A serum cortisol threshold value of >17.60 IU/L seemed to be associated with postpartum depressive symptoms, low birth weight, and lower weight for length/height z-score. No significant association was found between serum cortisol and infants reduced head circumference, the sum of skinfold thickness, and crown-rump length. Conclusion: Our results support the hypothesis that higher maternal cortisol levels may adversely affect a mother's mental health and birth outcomes. These findings have implications for understanding maternal mental health and early developmental psychopathology, both of which are well-known but understudied. Future studies should explore this association at various gestational ages and use epigenetic markers to determine hypothalamic-pituitary axis (HPA) activity during pregnancy and its effect on birth outcomes.