I’ve had a thyroid disorder for a few years and during this time I’ve learned about the thyroid and iodine, the nutrient the thyroid needs to function. Though many people have thyroid problems - 2 billion worldwide - it is most devastating when it happens to a baby in the womb.
Iodine deficiency is the most common cause of fetal brain damage and mental retardation in the world.
For most adults, iodine deficiency is barely noticed. At least one woman in eight will develop a thyroid disorder during her lifetime but about 60% of those women will be completely unaware of their condition. You may be reading this and thinking it doesn’t apply to you, but you may be one of the 60% who are completely unaware that they have an underactive thyroid. So please keep reading, especially if you’re pregnant, because having a thyroid disorder puts your unborn baby at risk of brain damage.
Iodine is needed for the production of thyroid hormone and thyroid hormone is critically important for the development of all parts of the fetal body - especially the brain and myelin sheath that protects the baby’s nerves. Even modest degrees of iodine deficiency can be associated with impairments of intellectual development in children.
A woman’s iodine requirements increase substantially during pregnancy and breastfeeding to ensure adequate supply to the fetus. Women who are breastfeeding secrete iodine into breast milk, concentrated at levels 20 to 50 times higher than what's circulating in the blood. For a breastfed infant, the mother’s breast milk is going to be the baby’s only source of iodine.
Our bodies do not produce iodine, we need to get it from our diet. A pregnant woman may not know that she has insufficient iodine. When iodine intake is poor, the body cannot produce enough thyroid hormones.
All women should insist on general thyroid function screening at the onset of pregnancy, as well as during pregnancy. Google 'maternal thyroid in pregnancy’ and speak to your doctor.
Here are 2 studies:
The Effect of Iodine Deficiency during Pregnancy on Child Development
Dr. Sarah Bath, Cambridge University Press
Iodine deficiency during pregnancy is linked to impaired brain development and has been noted as the greatest preventable cause of brain damage, with effects on cognitive and motor function, hearing and speech. Even mild-to-moderate iodine deficiency during pregnancy may be associated with subtle impairments in cognition and school performance. As global efforts to eradicate iodine deficiency in populations continue, it is more likely that mild-to-moderate, rather than severe, iodine deficiency will be the issue of concern in pregnancy, and therefore further research in regions of mild-to-moderate deficiency is required to strengthen the research base and to inform public-health policy.
Iodine Deficiency in Pregnancy: The Effect on Neurodevelopment in the Child
Dr. Sheila Skeaff, Research Professor, Department of Human Nutrition,University of Otago, Dunedin, New Zealand.
Iodine is an integral part of the thyroid hormones, thyroxine (T4) and tri-iodothyronine (T3), necessary for normal growth and development. An adequate supply of cerebral T3, generated in the fetal brain from maternal free T4 (fT4), is needed by the fetus for thyroid hormone dependent neurodevelopment, which begins in the second half of the first trimester of pregnancy. Around the beginning of the second trimester the fetal thyroid also begins to produce hormones but the reserves of the fetal gland are low, thus maternal thyroid hormones contribute to total fetal thyroid hormone concentrations until birth. In order for pregnant women to produce enough thyroid hormones to meet both her own and her baby’s requirements, a 50% increase in iodine intake is recommended. A lack of iodine in the diet may result in the mother becoming iodine deficient, and subsequently the fetus. In iodine deficiency, hypothyroxinemia (i.e., low maternal fT4) results in damage to the developing brain, which is further aggravated by hypothyroidism in the fetus. The most serious consequence of iodine deficiency is cretinism, characterised by profound mental retardation. There is unequivocal evidence that severe iodine deficiency in pregnancy impairs brain development in the child.