This prospective observational study aimed to assess the association between maternal 3rd trimester cortisol levels and early longitudinal language development in offspring, while also exploring potential sex differences in this association. The study utilized data from the Odense Child Cohort, comprising 1,093 mother-child dyads (570 boys and 523 girls).
Results indicated that cortisol levels were higher in women carrying a girl compared to women carrying a boy. Higher 3rd trimester maternal cortisol levels were positively associated with the development of productive vocabulary in boys at ages 12-21 months and 22-37 months. Furthermore, higher maternal cortisol levels in the 3rd trimester were positively associated with receptive vocabulary in girls at 12-21 months of age. These findings suggest that maternal 3rd trimester cortisol levels are positively associated with early language development in children aged 12-37 months.
Introduction:
Language development during early childhood is a critical milestone that reflects fetal neurodevelopment. Prenatal exposure to cortisol, a hormone associated with stress response, has been shown to impact fetal brain maturation. However, further research is needed to understand the specific influence of cortisol on language development in offspring.
Methods:
The study utilized data from the Odense Child Cohort, a population-based cohort in Denmark. The cohort included 1,093 mother-child dyads, consisting of 570 boys and 523 girls. Maternal fasting morning serum cortisol levels were collected during the 3rd trimester (gestational week 26-28) and quantified using liquid chromatography–tandem mass spectrometry. The main outcome measures included assessments of receptive and productive vocabulary using parent reports from the MacArthur-Bates Communicative Development Inventories. Parent reports were completed every three months from child age 12 to 37 months, providing longitudinal data on language development.
Results:
Analysis of the data revealed that maternal cortisol levels were higher in women carrying a girl compared to women carrying a boy. Furthermore, higher maternal cortisol levels during the 3rd trimester were positively associated with the development of productive vocabulary in boys at ages 12-21 months and 22-37 months. Additionally, higher maternal cortisol levels were positively associated with receptive vocabulary in girls at 12-21 months of age.
And….
The association between maternal cortisol levels during the 3rd trimester and early language development in children can be explained by various biochemical and physiological processes occurring in the body. Here is a detailed explanation of the chemical connections involved:
- Cortisol Production: Cortisol is a steroid hormone produced by the adrenal glands in response to stress. During pregnancy, cortisol levels naturally increase as part of the normal physiological changes. The placenta, which connects the mother and the fetus, also produces cortisol.
- Placental Transfer: Maternal cortisol can cross the placenta and reach the developing fetus. This transfer occurs through passive diffusion and active transport mechanisms. The presence of cortisol in the fetal environment can influence the development of various organ systems, including the brain.
- Fetal Brain Development: Cortisol plays a critical role in fetal brain development, particularly in areas associated with language processing. It acts on specific receptors in the brain, including the glucocorticoid receptors, which are involved in regulating gene expression and neuronal maturation.
- Neurogenesis and Synaptogenesis: Cortisol affects neurogenesis, the process of generating new neurons, and synaptogenesis, the formation of connections between neurons. It promotes the survival and differentiation of neurons, contributing to the development of neural circuits involved in language acquisition and processing.
- Myelination: Cortisol also influences myelination, the process of forming a protective coating called myelin around nerve fibers. Myelin facilitates efficient signal transmission between neurons. Proper myelination is essential for the development of neural pathways involved in language processing.
- Neurotransmitter Regulation: Cortisol can modulate the activity of various neurotransmitters in the brain. For example, it interacts with the serotonergic system, which plays a role in mood and cognitive functions, including language. Cortisol can affect the release and reuptake of neurotransmitters, thereby influencing neuronal communication and language-related processes.
- Gene Expression: Cortisol acts as a signaling molecule that can impact gene expression patterns in developing cells. It can activate or suppress certain genes involved in brain development, influencing processes such as neuronal proliferation, differentiation, and synaptic plasticity.
- Hormonal Interactions: Cortisol interacts with other hormones involved in fetal development. For instance, cortisol levels can influence the production and activity of sex hormones, which may contribute to sex-specific differences observed in language development.
- Epigenetic Modifications: Cortisol can induce epigenetic modifications, which are changes in gene function without altering the DNA sequence. Epigenetic mechanisms, such as DNA methylation and histone modifications, can influence gene expression patterns and contribute to long-lasting effects on brain development and function.
Impact of Covid-19 on cortisol
The COVID-19 pandemic has posed significant challenges to global health, affecting individuals of all age groups, including pregnant women. Emerging evidence suggests that the infection and associated stressors may impact maternal cortisol levels during pregnancy. This detailed exploration aims to elucidate the link between COVID-19 and high cortisol levels in pregnant women.
- Immune Response and Stress: COVID-19 is caused by the SARS-CoV-2 virus, which elicits a robust immune response in infected individuals. The immune response triggers the release of pro-inflammatory cytokines and activates the hypothalamic-pituitary-adrenal (HPA) axis, leading to an increase in cortisol production.
- HPA Axis Activation: The HPA axis is a complex hormonal system involved in stress response regulation. In response to stressors like infection, the hypothalamus releases corticotropin-releasing hormone (CRH), which stimulates the anterior pituitary gland to secrete adrenocorticotropic hormone (ACTH). ACTH, in turn, stimulates the adrenal glands to release cortisol.
- Inflammatory Response and Cortisol: COVID-19 infection induces a significant inflammatory response characterized by the release of cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). These cytokines can directly stimulate the adrenal glands to produce cortisol and promote cortisol synthesis in various tissues.
- Maternal Stress and Cortisol: The COVID-19 pandemic has brought unprecedented stress and anxiety to pregnant women. Psychological stress can activate the HPA axis, leading to increased cortisol production. Fear, social isolation, concerns about fetal health, and uncertainties regarding the pandemic contribute to elevated stress levels in pregnant women.
- Impact on Fetal Development: Elevated maternal cortisol levels can potentially impact fetal development. Prolonged exposure to high cortisol levels may disrupt the delicate balance of hormones necessary for fetal growth and development, including brain development and the development of stress response systems in the fetus.
- Placental Adaptation and Cortisol Metabolism: The placenta plays a crucial role in regulating the transfer of cortisol from the mother to the fetus. Placental enzymes, such as 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), convert cortisol to its inactive form, cortisone, thus protecting the fetus from excessive cortisol exposure. However, increased maternal cortisol levels due to COVID-19 may overwhelm the placental regulatory mechanisms, potentially leading to increased cortisol exposure in the fetus.
- Long-Term Effects on Offspring: Elevated cortisol levels during pregnancy have been associated with adverse outcomes in offspring, including altered neurodevelopment, increased risk of behavioral and emotional problems, and altered stress response systems. Long-term studies are needed to determine if the maternal cortisol elevation induced by COVID-19 has similar effects.
The COVID-19 pandemic and associated stressors have the potential to influence maternal cortisol levels during pregnancy. The interplay between viral infection, immune response, psychological stress, and cortisol production may contribute to elevated cortisol levels in pregnant women. Understanding the link between COVID-19 and high cortisol levels is vital for optimizing maternal and fetal health during this challenging time.
Conclusion:
The findings of this study suggest a positive association between maternal cortisol levels during the 3rd trimester and early language development in children aged 12-37 months. Specifically, higher cortisol levels were associated with enhanced productive vocabulary in boys and receptive vocabulary in girls.
These results contribute to our understanding of the prenatal factors that influence language development and highlight the potential importance of maternal cortisol levels in fetal neurodevelopment. The study was supported by the Novo Nordisk Foundation through a collaborative grant aimed at characterizing and mitigating the adverse effects of glucocorticoid treatment
referencee link : https://www.endocrine-abstracts.org/ea/0090/ea0090p449
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9029063/
