Prenatal stress and infants' development: association with cortisol and leptin levels in cord blood and saliva

Introduction: Stressful events during pregnancy may affect cognitive and somatic development in infants and increase the risk of developmental disorders in future. This study aimed at assessing the correlation between prenatal stress with salivary cortisol and leptin levels with a focus on infant development. Methods: In this prospective correlative study, 80 infants whose mothers were admitted to clinics during pregnancy were evaluated. The pregnant women were included during 24-28 weeks of pregnancy and assessed using the perceived stress scale until delivery. Following delivery, growth and development of infants were evaluated using the Ages and Stages Questionnaire (ASQ) at birth as well as 2, 4 and 6 months after birth. For assessing leptin and cortisol levels, cord blood and salivary samples were collected at birth and 6 months after birth, respectively. Results: The mean perceived stress score (PSS) during pregnancy was associated with infant development and weight at 2 and 6 months of age, respectively. Moreover, there was a negative association between leptin level at 6 months of age and infant height at 2, 4 and 6 months after birth. Finally, a negative correlation was observed between cortisol level at 6 months of age and infant height at 2 months following birth. Conclusion: The results indicated that the PSS of the mothers negatively correlated with the infants' growth, development and cortisol and leptin levels. Thus, prenatal stress probably affects growth and development in infancy through effects on the neuroendocrine system. Leptin might be an appropriate biomarker for determination of growth and development in infancy.