Thyroid disorder is one rising endocrine disorder may be due to awareness of the public and easy availability of thyroid function tests (TFT), each year the incidence of thyroid disorders is increasing. In pregnancy, TFT routinely is checked, and this has led to increasing findings of thyroid disorder in pregnancy.
The common form of thyroid disorder in pregnancy.
1) Gestational transient thyrotoxicosis (GTT)
2) Hypothyroidism
3) Hyperthyroidism
4) Postpartum Thyroiditis
5) Thyroid nodules
1) Gestational transient thyrotoxicosis (GTT):
During the first trimester there is high hCG and increased physiologic thyroid stimulation, especially in primi-gravida, twin pregnancies, and hyperemesis gravida. The blood picture of GTT is quite confusing, detailed history and physical examination are very important for diagnosis, as TSH might be suppressed. GTT is self-limited and use of antithyroid might risk birth defects.
2) Hyperthyroidism:
Grave’s disease, an autoimmune disorder, is most common in young women. But overactive thyroid gland in pregnancy is approximately 0.2% of women because pregnancy tends to suppress autoimmune responses. Grave’s disease in pregnancy is associated with increased pregnancy loss and serious medical complications for both the mother and the infant. All hyperthyroid pregnant women should be evaluated clinically and diagnosis is confirmed with TRaB and should be treated with trimester-specific antithyroid drug or surgically in the 2nd trimester.
3) Hypothyroidism:
Hashimoto thyroiditis is the cause of hypothyroidism in pregnancy. Symptoms of underactive hypothyroidism are the same as in general populations. Treatment of hypothyroidism is important because thyroid hormones are important to a baby’s brain and nervous system development, untreated hypothyroidism especially during the first trimester can cause low IQ and problems with normal development. Untreated hypothyroidism during pregnancy can lead to preeclampsia, a dangerous rise in blood pressure in late pregnancy, anemia, miscarriage, low birth weight, stillbirth, and congestive heart failure, rarely. Dose adjustment of levothyroxine is done by trimester-specific TSH range.
4) Postpartum thyroiditis:
Postpartum thyroiditis is an inflammation of the thyroid that affects about 1 in 20 women during the first year after giving birth. Stages of presentation: hyperthyroidism, hypothyroidism, and later become euthyroid. Not all women who have postpartum thyroiditis goes through both phases. Some only go through the hyperthyroid phase, and some only through the hypothyroid phase. The hyperthyroid stage of postpartum thyroiditis rarely needs treatment. If your symptoms are bothering, the doctor may prescribe a beta-blocker. If there are symptoms during the hypothyroid stage levothyroxine can be prescribed.
5) Thyroid nodules:
The benign form of thyroid nodule does not need intervention during pregnancy. Thyroid cancer is the most common endocrine malignancy affecting pregnant women. The types of cancers seen in pregnant women are the same as in non-pregnant women. Well-differentiated cancer surgery can be done in the immediate postpartum period, whereas not well-differentiated cancers, surgery can be done in the second trimester. Post-surgery, radioiodine scan, and ablation are absolutely contraindicated during pregnancy and lactation.
By Dr. Amrit Rijal
MBBS (NMCTH), MD (endocrinology & metabolism, Bangladesh)
Consultant Endocrinologist
Charak Memorial Hospital, Pvt. Ltd., Pokhara