Know How The Thyroid Gland Impacts Foetal Development
World Thyroid Day is observed on May 25 and the day aims to raise awareness about the importance of the thyroid gland and thyroid-related disorders. The thyroid is a small gland in your neck and it produces hormones that have an impact on several body functions like metabolism, energy levels and growth among others. Similarly, the thyroid gland also influences several aspects of pregnancy, from birth weight to heart condition and foetal development.
It is important to understand the role of the thyroid in foetal development as it can lead to a healthy pregnancy and the long-term well-being of the child. Read on as Dr Piyush Lodha, Diabetologist and General Physician at Pune’s Ruby Hall Clinic explains how the thyroid gland impacts the foetus.
Maternal and Foetal Thyroid Function
Dr Lodha says that during the early stages of pregnancy, the foetus relies entirely on the mother for thyroid hormones. This dependency continues until the foetal thyroid gland becomes functional around the 10th to 12th week of gestation. However, even after the foetal thyroid starts producing hormones, maternal thyroid hormones remain important for foetal development.
“Maternal thyroid hormones cross the placenta and are critical for the early development of the foetal brain and other organs. Adequate levels of maternal thyroid hormones are essential for the proliferation and differentiation of neural cells, synaptogenesis, and myelination in the foetal brain. These processes are vital for the proper formation of the central nervous system and overall cognitive function.”
Impact on Neurological Development
The thyroid hormones also play an important role in the neurological development of the foetus. The thyroid hormone receptors are present in the brain of the foetus as early as the first trimester, highlighting their importance in neurodevelopment. Deficiencies in thyroid hormones during pregnancy can lead to severe developmental issues.
- Congenital Hypothyroidism: This is a condition wherein when the foetal thyroid gland is underactive or absent. Without early detection and treatment, it can result in intellectual disabilities, growth retardation and other neurodevelopmental disorders.
- Maternal Hypothyroidism and Iodine Deficiency: Inadequate thyroid hormone levels in the mother can lead to cretinism that is characterised by severe intellectual disability, stunted growth and other physical abnormalities.
Role in Physical Development
Dr Lodha says that beyond its role in brain development, the thyroid hormones also play an important role in the physical development of the foetus. They impact the growth and maturation of various tissues and organs, including the skeletal system, heart, and lungs.
- Skeletal Development: Thyroid hormones regulate the growth and differentiation of bone cells. Adequate levels are necessary for normal bone growth and mineralisation, ensuring that the foetus develops a healthy skeletal structure.
- Cardiovascular System: Thyroid hormones influence heart rate, cardiac output, and vascular resistance. Proper thyroid function is vital for the development of the foetal cardiovascular system, ensuring efficient blood circulation and oxygen delivery to tissues.
- Lung Maturation: Thyroid hormones are involved in the maturation of the foetal lungs, preparing them for breathing after birth. They stimulate the production of surfactant, a substance that reduces surface tension in the lungs and is essential for normal respiratory function.
Implications for Pregnancy and Birth Outcomes
Dr Lodha highlights that dysfunction in the thyroid during pregnancy can lead to various complications for both the mother and the foetus. “For the mother, it can increase the risk of preeclampsia, gestational hypertension, and preterm birth. For the foetus, it can result in low birth weight, preterm delivery, and congenital anomalies.”
He adds, “The thyroid gland’s role in foetal development is multifaceted and critical for ensuring a healthy pregnancy and optimal long-term outcomes for the child.”
