Resistance to thyroid hormone is characterised by defects in the thyroid hormone receptors due to pathogenic genetic variants, resulting in reduced responsiveness to the action of thyroid hormone.

In around 2%–5% of couples who experience recurrent miscarriage, there is a genetic cause. This is most commonly a balanced structural chromosomal anomaly, often a balanced translocation.

There will be a genetic cause for some cases of intrauterine death (IUD) or stillbirth.