TABLET trial

Randomised Controlled Trial of the Efficacy and Mechanism of Levothyroxine Treatment on Pregnancy and Neonatal Outcomes in Women with Thyroid Antibodies (TABLET)

TABLET trial summary 

TABLET is a large double blind placebo controlled trial to be run across approximately 20 UK sites.  This trial is testing the hypothesis that taking a small (50µg) dose of thyroxine by euthyroid women aged between 16 and 40, with thyroidperoxidase (TPO) antibodies, before and during pregnancy, will increase their chance of delivery beyond 34 weeks of gestation by 10%, compared with the placebo.

 A systematic review of literature has found that thyroid antibodies are associated with miscarriage and pre-term births. Recruitment will be taking place in miscarriage clinics and infertility clinics in hospitals in England and Scotland. We will be asking women who have miscarried, and plan to be actively trying to conceive within the next year, and more recently, women who are being treated for infertility, to have a screening blood test for thyroid antibodies.  Women whose tests indicate that they are TPO positive, and are euthyroid, will be asked to consent to be randomised into the trial. We anticipate that we will test over 5000 women, to randomise 900 into the trial.  The intervention of 50µg of thyroxine or placebo will be taken daily for up to one year, whilst the woman is trying to conceive, and throughout the pregnancy. Thyroid function (TSH and Free T4 levels) will be closely monitored at regular intervals throughout the trial. Women whose thyroid function results fall out of the ranged defined by the Trial Management Group will be withdrawn from the trial, and treated according to standard guidelines. 


EudraCT Number: 20011-000719-19

ISRCTN Number: 15948785

Funder: Efficacy and Mechanism Evaluation Programme

Sponsor: University of Birmingham

Chief  Investigator: Professor Arri Coomarasamy

Trial Coordinating Centre: Birmingham Clinical Trials Unit, University of Birmingham