Your thyroid is responsible for many bodily processes. It is a gland found in the neck that controls how quickly your body uses energy, makes proteins, and it controls your body’s sensitivity to other hormones. Sometimes, the thyroid does not perform correctly. Hypothyroidism is abnormally low thyroid function, and adults with hypothyroidism may experience very subtle symptoms including fatigue, constipation, swelling of the legs, and depression. However, hypothyroidism in pregnant women can have a more serious effect on their future children. A recent study was designed to determine whether or not a mother’s hypothyroidism might have a negative effect on the intelligence of her child. Mental retardation has been linked to hypothyroidism for nearly a hundred years. Yet, studies that have tested such an association in the past do not usually discern whether or not the hypothyroidism is present in just the mother, or if she passed it on directly to her child. According to the results of the recent study, pregnant women suffering from hypothyroidism did, in fact, have children that scored lower on IQ and general intelligence tests. However, the children of the women with hypothyroidism who were being treated during pregnancy did not score as low on these tests. In other words, if you have deficient thyroid function during your pregnancy, it is likely that your child will not develop to their full mental potential. The reason such a deficiency negatively affects babies is that they do not develop their own thyroid gland until approximately 12 weeks gestation. Until then, the mother is the only source of thyroid hormones, which are directly related to development. If a woman’s own thyroid is highly underactive, it will only create enough hormones for her body and not enough for that of her baby. If you are pregnant or considering having a child in the near future, you should absolutely be screened systematically to check for hypothyroidism. If the deficiency is minor, you might not experience any symptoms, but it does not mean your fetus will not be affected. If you have a prenatal examination test positive for hypothyroidism, you should begin treatment right away and continue through the duration of your pregnancy, especially within the first 12 weeks. While the prospect of having a child with mental deficiencies is frightening, stay calm if you find out that you have an underactive thyroid. Thyroid treatment can usually prevent such an outcome. Source: Jens Henrichs et al: Maternal Thyroid Function during Early Pregnancy and Cognitive Functioning in Early Childhood. The Journal of Clinical Endocrinology & Metabolism Volume 95 Issue 9 September 2010