What is gestational transient thyrotoxicosis?

Gestational transient thyrotoxicosis (GTT) is a temporary condition of an overactive thyroid in pregnant women caused by high levels of one of the main pregnancy hormones (HCG). In this condition, you will have raised FT4 and low TSH levels in early pregnancy.

Does it mean I have an overactive thyroid?

Although you may experience some symptoms in common with hyperthyroidism (intolerance to heat, tremors, anxiety, palpitations etc.), you are unlikely to be positive for the thyroid antibodies linked to hyperthyroidism (TRAb). You are also unlikely to have any of the other signs or symptoms associated with a true underlying overactive thyroid e.g. a goitre, eye symptoms, weight loss before pregnancy or a personal or family history of thyroid disease with this condition. If you have significant nausea (feeling sick) and vomiting (being sick), it is more likely to be GTT.

Does it put my pregnancy at higher risk?

GTT does not put your pregnancy at higher risk and usually clears up by itself by the end of the first or early second trimester.

Do I need treatment?

It usually does not require treatment with antithyroid drugs. If you are experiencing a rapid heart rate your doctor may give you a treatment called beta blockers to help this.

Read the RCOG Green-top guideline on the Management of Thyroid Disorders in Pregnancy