A pregnant woman’s iodine intake can have lasting implications for her baby’s brain development, yet the importance of this essential nutrient often receives less attention than other aspects of prenatal nutrition, experts said on the occasion of Global Iodine Deficiency Disorders Prevention Day, observed on October 21.
“Iodine is needed to produce thyroid hormones that support the development of the foetal brain and nervous system, particularly during pregnancy and early life. A deficiency can lead to thyroid dysfunction and, in severe cases, irreversible developmental damage,” said Dr Soma Saha, Endocrinologist and Diabetologist from AIIMS, New Delhi.
The requirement for iodine increases during pregnancy to support both the mother and the developing baby. Recommended daily intake varies across guidelines: the US recommendations suggest 220 micrograms during pregnancy, while the World Health Organisation recommends 250 micrograms a day.
Dr Shuchi Rastogi, Consultant Obstetrics & Gynaecology and IVF at Follicles, IVF Sector 10, Noida, concurred with Dr Saha as she said, “Adequate iodine intake is important for thyroid function, fertility and a healthy pregnancy. Iodine deficiency can cause thyroid dysfunction, potentially affecting ovulation and pregnancy outcomes. For women planning pregnancy or undergoing IVF, ensuring adequate iodine nutrition and assessing thyroid function when indicated are important aspects of preconception care.
“Using iodised salt and seeking medical advice about prenatal iodine requirements can help protect maternal health and support the baby's early brain development.”
The importance of iodine nutrition has also been highlighted by a study of more than 1,500 pregnant women in Ireland. Published in the European Journal of Nutrition in 2025, the research found that 60% of participants had suboptimal iodine status. Their median urinary iodine concentration was 125 micrograms per litre, below the WHO threshold of 150 micrograms per litre used to assess iodine sufficiency in pregnant populations.
The study, led by researchers including Dr Áine Hennessy of University College Cork, examined iodine status among women expecting their first child at Cork University Maternity Hospital.
It found that iodine status varied with factors including age, body mass index, education, supplement use and season. Notably, around two-thirds of participants reported taking pregnancy supplements containing iodine, yet many still had suboptimal iodine status. The findings point to the need for better awareness and dietary guidance, although they do not establish the prevalence of iodine deficiency among pregnant women in India.
“Iodine deficiency is one of the most common micronutrient deficiencies worldwide; there is little public awareness of the important role that iodine plays in brain development during pregnancy," said Dr Áine Hennessy, lead researcher of the study.
"Our findings are particularly concerning, as most women in the study were considered healthy and low risk, and two-thirds reported taking pregnancy supplements containing iodine. This suggests that additional public health measures may need to be addressed."
In India, the national programme to prevent iodine deficiency disorders began in 1962 and was expanded and renamed the National Iodine Deficiency Disorders Control Programme in 1992. Universal salt iodisation remains its principal strategy, but surveys show that ensuring households use salt with sufficient iodine continues to be important.
The India Iodine Survey 2018-19, which covered 21,406 households, found that 76.3% had edible salt containing at least 15 parts per million of iodine. It also reported differences between states and a median urinary iodine concentration of 173.4 micrograms per litre among pregnant women, within the WHO’s adequate range for assessing iodine nutrition in pregnant populations. Meanwhile, the National Family Health Survey 2019-21 found that about 94% of households used iodised salt. The figures are not directly comparable because the surveys assessed different aspects of salt use and iodine content.
Dr Ravinder Goswami, a professor in the Department of Endocrinology and Metabolism at AIIMS, New Delhi, said India’s iodine-control programme had helped address deficiency, but continued monitoring and public awareness remained necessary. Iodine deficiency can cause goitre, an enlargement of the thyroid gland that may lead to visible swelling in the neck and, in some cases, pressure-related symptoms.
Doctors advise households to use adequately iodised salt rather than assume that every variety contains iodine. “Those who use pink sendha namak or black salt, particularly during fasting, should check the product label or confirm with the manufacturer whether it is iodised,” added Dr Saha.
Salt should be stored in a covered container in a cool, dry place, away from heat and moisture. Adding it towards the end of cooking may also help limit iodine losses. Milk, dairy products, eggs and fish can contribute to iodine intake, although the amount varies depending on the food and production practices, said the doctors.
Dr Saurav Das, Consultant Endocrinologist, Apollo Hospitals Guwahati, too maintained that iodine is indispensable for thyroid function, physical growth and optimal brain development.
“Its deficiency can cause thyroid disorders and irreversible intellectual impairment known as cretinism, particularly when it occurs during pregnancy and early infancy. These can be detected and acted upon early through wider coverage under universal newborn screening programmes to prevent such irreversible damage.
“Universal access to adequately iodised salt, sustained public awareness and strengthened maternal and perinatal healthcare are essential public health priorities,” he added.
For women planning a pregnancy, the Irish researchers advised paying attention to iodine-rich foods and checking whether their diet provides enough of the nutrient. Those following vegan or predominantly plant-based diets may need to choose iodine-fortified alternatives. The researchers cautioned against kelp or seaweed supplements, which can contain excessive iodine and affect thyroid function.
