Thyroid disease and pregnancy interact in important ways — both for mother and baby. Here is the essential guide.
Hypothyroidism in pregnancy
Untreated hypothyroidism increases risk of miscarriage, pre-eclampsia and impaired fetal brain development. Thyroxine requirements typically rise by 25–30% in the first trimester.
Hyperthyroidism in pregnancy
Usually treated with the lowest effective dose of propylthiouracil in the first trimester then carbimazole. Surgery is reserved for severe or resistant cases in the second trimester.
Thyroid nodules and pregnancy
Newly discovered nodules are evaluated with ultrasound and FNAC. Most surgery can be safely deferred to after delivery.
Post-partum thyroiditis
A transient autoimmune flare affecting around 5% of women — usually self-limiting but needs monitoring.
Pre-pregnancy planning
Optimise thyroid function before conception — TSH ideally between 0.5 and 2.5 mIU/L.