Investigators:

Project lead: Dr Arri Coomarasamy

Institutions:

BTF involvement: Letter of support for funding

Timescale: It is anticipated that the trial will last for 4 years and 4 months (52 months in total), starting 1st August 2010.

Approximately 10-20% of women of child-bearing age have thyroid antibodies. In such women, the risks of miscarriage and preterm birth are more than doubled compared with those who do not have thyroid antibodies. Miscarriage is the commonest complication of pregnancy, affecting 1 in 5 women. Preterm birth occurs in 6-10% of pregnancies. Up to 85% of new-born deaths are due to preterm births, and of those who survive, approximately 10% suffer long-term disability. The human cost of preterm birth is therefore enormous; the financial cost of preterm birth is estimated at £939 million/year in the UK.

There is evidence from two small studies that giving levothyroxine tablets to women with thyroid antibodies may halve the risk of miscarriages and preterm births. However, the evidence is not strong enough for recommending levothyroxine treatment: we surveyed 183 clinicians (endocrinologists and obstetricians), and 85% of them said they required more research before they would be confident to use this treatment in routine practice. We are, therefore, proposing a large and high quality trial to study this question, with live birth beyond 34 weeks of pregnancy as the primary outcome. This trial is called the TABLET (Thyroid AntiBodies and LEvoThyroxine) study, and 21 hospitals in the UK are scheduled to take part in this study. Evaluation of Efficacy and Mechanism (EME) programme of the Medical Research Council (MRC, UK) has provisionally agreed to fund the TABLET study.

Dr A Coomarasamy

April 2010