Information and support I am Living with a thyroid condition Positive antibodies but normal thyroid function Positive antibodies but normal thyroid function If you have positive thyroid peroxidase antibodies (TPOab) with TSH and FT4 within the reference range there is a risk of later developing hypothyroidism, as well as miscarriage, premature birth and thyroid function abnormalities postpartum. Levothyroxine treatment, however, is not recommended as it does not reduce these risks if the thyroid function is normal. Before pregnancy You should have your thyroid function monitored every 6 months while planning a pregnancy. During pregnancy If you become pregnant, your thyroid function should be rechecked at 7-9 weeks and again at 20 weeks. Repeat TPOab testing is not needed. If you are found to be hypothyroid, you will be treated with levothyroxine. Should all pregnant women have their thyroid function tested? The RCOG guideline recommends that doctors do not need to check all pregnant women's thyroid levels or their thyroid peroxidase antibodies (TPOab) at their pregnancy booking appointment. Read about the Thyroid Antibodies and Levothyroxine (TABLET) trial Read the RCOG Green-top guideline on the Management of Thyroid Disorders in Pregnancy Manage Cookie Preferences Please ensure Javascript is enabled for purposes of website accessibility