Thyroid antibodies are associated with an increased risk of miscarriage and premature delivery, even when thyroid function is normal. The TABLET trial was a randomised, double-blind, placebo-controlled trial to investigate whether treatment with levothyroxine would increase live-birth rates among euthyroid women who had positive peroxidase antibodies and a history of miscarriage or infertility.

The conclusions were that the use of levothyroxine in euthyroid women with peroxidase antibodies did not result in a higher rate of live births. Details of the results of the trial are published in an article in the New England Journal of Medicine. 

More information is available on the TABLET trial website