The functioning of the thyroid gland remains normal during pregnancy, but the body’s needs for iodine are greater due to the need to provide the needs of the fetus. The fetal thyroid gland begins to function between the second and third gestational months. The thyroid hormones thus produced play a role in the development of his brain and nervous system. Iodine and maternal thyroid hormones that cross the placenta are also important factors in fetal thyroid function. For this reason, any disturbance of thyroid functions in the mother should be detected early and treated as indicated. Thyroid diseases affect about 4% of pregnant women, but most of these conditions are detected and treated effectively without causing serious difficulties for the mother during pregnancy or risk to the fetus. Some women undergo systemic thyroid monitoring during pregnancy. These are: Patients with a personal or family history of thyroid gland diseases; Patients who have a diagnosed autoimmune disease; Patients previously treated for hyperthyroidism. Treatment of hypothyroidism in pregnant women If untreated, hypothyroidism during pregnancy can have serious consequences both for the mother – increased risk of miscarriage, hypertension and preeclampsia, and for the fetus – retardation of the psychomotor development of the newborn. In pregnant women with hypothyroidism, blood levels of TSH and thyroid hormones should be monitored very regularly – at least every two months. During pregnancy, the treatment of hypothyroidism is based on taking synthetic thyroid hormones – levothyroxine. This intake of levothyroxine is safe for the fetus and should not be discontinued under any circumstances without medical advice. When the patient was already on prescribed therapy before pregnancy, her levothyroxine requirements increased by 30 to 50% during fetal wear. Thanks to the regular measurements of TSH in the blood, it is possible to precisely adjust the dose. Taking thyroid hormones is possible during breastfeeding, under medical supervision. References: https://www.vidal.fr/maladies/metabolism-diabete/hypothyroidie/grossesse.html