Management Thyroid Disease in Pregnancy: Preconception, and the postpartum complications

Pregnancy has a profound impact on the thyroid gland and thyroid function since the thyroid may encounter changes to hormones and size during pregnancy. The diagnosis and treatment of thyroid disease during pregnancy and the postpartum is complex but knowledge regarding the interaction between the thyroids and pregnancy/the postpartum period is advancing at a rapid pace. For women known to have hypothyroidism, an increase in thyroxine dose by 20–40% when pregnancy is confirmed usually ensures they remain euthyroid. Treatment of subclinical hypothyroidism is recommended if the woman has antithyroid antibodies. Treatment of hyperthyroidism, unless it is related to human chorionic gonadotrophin, involves propylthiouracil in the first trimester. Carbimazole may be used in the second trimester. Thyroid function tests are checked every month and every two weeks following a change in dose. Women with a current or a past history of Graves’ disease who have thyrotropin receptor antibodies require early specialist referral as there is a 1–5% risk of fetal hyperthyroidism. Women with thyroid disorders in pregnancy should be followed up by their GP in the postpartum period. Postpartum thyroiditis may present months after delivery.