When to worry about tiredness in pregnancy with an underactive thyroid

An underactive thyroid can contribute to low energy, feeling unusually cold, constipation, dry skin, difficulty concentrating, and a slower-than-usual pulse. Pregnancy can cause tiredness for other reasons, so symptoms need to be interpreted with thyroid blood tests. A change in symptoms does not by itself show whether thyroid hormone levels are too low or treatment needs adjusting.

Tell your maternity or thyroid-care team if tiredness is increasing, affects daily activities, or comes with new thyroid-related symptoms. Take prescribed thyroid medicine consistently and ask how to separate it from iron or calcium products, which can interfere with absorption. Keep planned blood tests and appointments; do not alter the dose without clinical advice.

Seek urgent care for severe breathlessness, chest pain, fainting, confusion, extreme drowsiness, or a sudden major decline. Contact your maternity team promptly for persistent dizziness, a very slow or irregular heartbeat, inability to keep medicines down, or symptoms that make walking or caring for yourself unsafe. Use your local emergency service for a life-threatening problem.

Ask when your thyroid blood tests should be repeated, what result or symptom should prompt an earlier review, and how to take medicine with pregnancy supplements. Ask who to contact after missed doses, vomiting, or a change in your prescription.