Doctor Advice for Thyroid Issues in Pregnancy

The thyroid gland produces hormones that regulate metabolism, energy production, and growth. During pregnancy, thyroid hormones play a critical role in fetal brain development, particularly in the first trimester before the baby's own thyroid gland becomes functional. Maternal thyroid dysfunction can therefore have significant implications for both the mother and the baby.

Pregnancy itself increases the demand on the thyroid gland, leading to physiological changes in thyroid hormone levels. The thyroid gland enlarges slightly, and thyroid hormone production increases by approximately 50 percent to meet the needs of the growing baby. Women with marginal thyroid function before pregnancy may develop frank thyroid dysfunction during gestation.

Thyroid disorders are common in India, with some studies estimating that up to 10 to 15 percent of pregnant women have some form of thyroid abnormality. Universal thyroid screening during pregnancy is increasingly recommended by Indian obstetricians, including those practising in Visakhapatnam, to ensure early detection and treatment.

Hypothyroidism, or an underactive thyroid, is the most common thyroid disorder in pregnancy. It is diagnosed when thyroid stimulating hormone (TSH) levels are elevated above the trimester-specific reference range. Symptoms include fatigue, weight gain, constipation, cold intolerance, dry skin, and mental sluggishness, though many of these overlap with normal pregnancy symptoms.

Untreated hypothyroidism during pregnancy is associated with increased risks of miscarriage, preeclampsia, placental abruption, preterm delivery, and impaired cognitive development in the child. The severity of these risks depends on the degree of thyroid deficiency and how early treatment is initiated.

Treatment involves levothyroxine, a synthetic thyroid hormone that is safe during pregnancy. The dose is determined by the TSH level and is adjusted through regular monitoring, typically every four to six weeks. Women who were already on thyroid medication before pregnancy often need a dose increase of 25 to 50 percent, and this adjustment should be made as early as possible under medical guidance.

Hyperthyroidism, or an overactive thyroid, is less common during pregnancy but equally important to manage. Symptoms include rapid heart rate, anxiety, tremors, weight loss, heat intolerance, and palpitations. The most common cause is Graves disease, an autoimmune condition that can be exacerbated or first manifest during pregnancy.

Uncontrolled hyperthyroidism poses risks including preterm birth, low birth weight, preeclampsia, and thyroid storm, a rare but life-threatening condition. Anti-thyroid medications such as propylthiouracil in the first trimester and methimazole in the second and third trimesters are used for treatment. The choice of medication and dose requires careful medical oversight.

It is important to distinguish true hyperthyroidism from the transient thyrotoxicosis of early pregnancy, which is caused by high hCG levels and resolves without treatment by the second trimester. Blood tests including TSH, free T4, and thyroid antibodies help the doctor make an accurate diagnosis and avoid unnecessary treatment.

Thyroid screening in pregnancy typically involves measuring TSH levels through a blood test. If TSH is abnormal, free T4 and thyroid antibody levels are measured to determine the type and cause of dysfunction. First-trimester screening is ideal, as early treatment is most effective in protecting fetal brain development.

Women with a history of thyroid disease, type 1 diabetes, other autoimmune conditions, or a family history of thyroid disorders are at higher risk and should be screened at the first prenatal visit. Many obstetricians in India now recommend universal screening given the high prevalence of thyroid disorders in the population.

Levothyroxine should be taken on an empty stomach, ideally 30 to 60 minutes before breakfast, for optimal absorption. Iron and calcium supplements, which are commonly prescribed during pregnancy, can interfere with levothyroxine absorption and should be taken at least four hours apart. The doctor can help create a dosing schedule that accommodates all medications.

Regular monitoring of thyroid function ensures that hormone levels remain within the target range throughout pregnancy. TSH targets during pregnancy are generally lower than in non-pregnant adults, and the doctor uses trimester-specific reference ranges to guide treatment. Adjustments to medication doses are common and expected.

After delivery, thyroid medication doses often need to be adjusted back to pre-pregnancy levels. Postpartum thyroiditis, an inflammation of the thyroid gland that can occur within the first year after delivery, affects some women and may cause temporary hyperthyroidism followed by hypothyroidism. Symptoms such as fatigue, mood changes, and weight fluctuations should be evaluated with thyroid function tests.

Women who had thyroid disorders during pregnancy should continue regular thyroid monitoring in the postpartum period and beyond. Thyroid health has implications for breastfeeding, future pregnancies, and long-term well-being. Maintaining a relationship with a healthcare provider who monitors thyroid function ensures ongoing optimal care.