Summary: New research suggests that higher maternal cortisol levels during the third trimester of pregnancy are associated with modest improvements in early speech and language skills in children. The study analyzed data from more than 1,000 Danish mother–child pairs and found sex-specific differences in how prenatal cortisol exposure related to early language milestones.
Researchers examined cortisol measurements collected from pregnant women in their third trimester and compared those levels to language outcomes measured in children between 12 and 37 months of age. The findings indicate that boys whose mothers had higher prenatal cortisol levels tended to produce a larger spoken vocabulary during toddlerhood, while girls showed stronger receptive language (understanding) earlier in infancy. These patterns provide new insight into the role of prenatal cortisol in fetal brain maturation and early child development.
The investigators emphasize that these results are observational and do not mean that stress during pregnancy is beneficial. Rather, cortisol is a natural steroid hormone that helps regulate fetal growth and brain development, and its varying prenatal levels may influence how language systems in the developing brain mature.
Key Facts:
- Elevated maternal cortisol during the third trimester is linked with specific gains in early language outcomes in offspring.
- In this study, boys exposed to higher prenatal cortisol produced more words between 12 and 37 months, whereas girls showed better word comprehension between 12 and 21 months.
- This is the first longitudinal study to examine maternal cortisol and child language development over time while accounting for offspring sex and maternal education level, offering new perspectives on prenatal cortisol’s role in fetal maturation.
Source: European Society of Endocrinology
High levels of the stress hormone cortisol during the third trimester of pregnancy may improve speech and language skills in the first three years of a child’s life, according to research presented at the 25th European Congress of Endocrinology in Istanbul.
Language milestones in early childhood are useful indicators of how the nervous system developed during pregnancy. Cortisol, a steroid hormone produced in response to stress, plays an important role in directing fetal growth and shaping brain circuits. Despite this biological importance, the specific effects of prenatal cortisol on early language acquisition have been poorly understood until now.
The study drew on data from the Odense Child Cohort. Researchers at Odense University Hospital analyzed cortisol measures taken from 1,093 Danish women during the third trimester and assessed language outcomes for 1,093 children between 12 and 37 months of age. By combining biological measures with standardized language assessments and accounting for key factors such as maternal education and child sex, the team sought to clarify whether prenatal cortisol exposure correlates with early language trajectories.
The main findings revealed a sex-specific pattern. Boys exposed to higher prenatal cortisol tended to have larger spoken vocabularies across the 12–37 month period. Girls exposed to higher maternal cortisol demonstrated stronger receptive language skills—meaning they understood more words—at earlier ages, specifically between 12 and 21 months. These associations persisted after taking into account potential confounders available in the cohort data.
“To our knowledge, this is the first study to investigate the association between maternal cortisol levels and language development in children over time, also taking offspring sex and maternal educational level into account,” said Dr Anja Fenger Dreyer, a member of the research team. She noted that the large cohort, rigorous analytic methods, and relevant covariate data strengthen the study’s contribution to understanding prenatal influences on child development.
The researchers plan to follow the cohort further to determine whether prenatal cortisol exposure has longer-term cognitive implications. The Odense Child Cohort includes cognitive testing data collected when children reach seven years old, and the team intends to examine whether higher prenatal cortisol levels are associated with later intellectual outcomes such as IQ scores.
“Early language development is a known predictor of later cognitive functions like attention, memory, and learning,” Dr Fenger Dreyer added. “We will investigate whether prenatal cortisol exposure relates to cognitive measures at age seven to better understand how early hormonal environments influence developmental trajectories.”
About this language development research news
Author: Joanna Williams
Source: European Society of Endocrinology
Contact: Joanna Williams – European Society of Endocrinology
Image: The image is credited to Neuroscience News
Original Research: The findings were presented at the European Congress of Endocrinology 2023