Cortisol levels in late pregnancy can predict sleep health of infants

Cortisol levels in late pregnancy can predict the sleep of infants, according to a new study to be presented at the SLEEP 2023 annual meeting.

Results show that newborns with higher levels of cortisol in their hair samples took longer to fall asleep at 7 months of age. Neonatal hair cortisol is a measure of fetal cortisol in the last trimester of pregnancy.

Although increases in cortisol across pregnancy are normal and important for preparing the fetus for birth, our findings suggest that higher cortisol levels during late pregnancy could predict the infant having trouble falling asleep. We are excited to conduct future studies to better understand this link."

Melissa Nevarez-Brewster, lead co-author, graduate student, University of Denver

The researchers collected hair cortisol from 70 infants in the first days after birth; 57% of the infants were female. Parents then completed a sleep questionnaire when their child was 7 months old. Analyses covaried for gestational age at birth and family income-to-needs ratio.

Tessa Benefield, lead co-author and research staff, noted that it will be important for future research to further study potential long-term effects of fetal cortisol production on sleep health through infancy into childhood.

"The results indicate that there may be prenatal influences on sleep health early in life, pointing to the need to better understand what factors may set the stage for better sleep health in infancy and beyond," she said.

This study was supported by funding from the National Institutes of Health. The research abstract was published recently in an online supplement of the journal Sleep and will be presented Tuesday, June 6, during SLEEP 2023 in Indianapolis. SLEEP is the annual meeting of the Associated Professional Sleep Societies, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.