You are currently using an unsupported browser which could affect the appearance and functionality of this website. Please consider upgrading to the latest version or using alternatives such as Mozilla Firefox, Google Chrome or Microsoft Edge.

Subclinical hypothyroidism and antithyroid autoantibodies in women with subfertility or recurrent pregnancy loss (Scientific Impact Paper No. 70)

This Scientific Impact Paper uses the latest evidence to provide information on thyroid testing and the management of mild thyroid problems and thyroid antibodies in women with a history of subfertility or recurrent miscarriages.

Plain language summary

The thyroid is a gland located in the neck and is important for many processes in the body. Problems with the thyroid gland are common in women of reproductive age.

It is essential to have a normal working thyroid gland in order to achieve a successful pregnancy.

One of the most common problems with the thyroid is underactivity (known as hypothyroidism). An early, mild form of an underactive thyroid is called subclinical hypothyroidism. Often people with this condition do not have any symptoms.

Another common problem is thyroid autoimmunity. Here, the immune system attacks the thyroid gland sometimes leading to the development of abnormal thyroid function. This can be diagnosed by the presence of proteins in the bloodstream called antibodies.

Mild thyroid problems and the presence of high levels of thyroid antibodies have been linked to miscarriage and premature birth.

There is debate in medicine about whether there should be routine testing of thyroid function in both the general population and individuals who are trying for a baby. In addition, the strategies used to manage certain thyroid problems are questioned.

Discussions around testing and subsequent management particularly relate to women with a history of subfertility or repeated miscarriages.

This Scientific Impact Paper provides information on thyroid testing, and management of mild thyroid problems and thyroid antibodies in women with a history of subfertility or recurrent miscarriages, using the latest evidence and guidelines.

It concludes that there may be a role for treating these women with thyroxine tablets (the hormone produced by the thyroid gland) when subclinical hypothyroidism exists, and gives guidance on the cut-off levels for treatment.

COVID disclaimer: This Scientific Impact Paper was developed prior to the emergence of the COVID-19 coronavirus.

Version history: This is the first edition of this paper.

Please note that the Scientific Advisory Committee regularly assesses the need to update. Further information on this review is available on request.