Endocrine disorders in family members linked to miscarriage risk

Being related to people with endocrine disorders, including type 2 diabetes, is associated with higher risk of miscarriage. 

Researchers from Denmark analysed data from national health registries to investigate the link between endocrine disorders, including diabetes, thyroid disease, polycystic ovary syndrome, and miscarriage. They found women with parents with an endocrine disorder had a six percent higher rate of miscarriage, and those with a sister with an endocrine disorder had a seven percent higher rate. Non-peer-reviewed results were presented at the 40th annual meeting of the European Society of Human Reproduction and Embryology (ESHRE) in Amsterdam on Wednesday 10 July 2024.

Dr Pia Egerup, from Copenhagen University Hospital Hvidovre, Denmark and lead author of the study, said: 'We believe that the mechanism linking familial endocrine disease and pregnancy loss could be a shared genetic background, predisposing individuals to both endocrine disease and pregnancy loss. 

'One potential mechanism could involve high-risk human leukocyte antigens (HLAs), which define the immune system's ability to distinguish 'good from bad'. Specific HLA types are known to be associated with several endocrine and autoimmune diseases and could also be associated with pregnancy loss.'

Authors highlighted that as only 60 percent of miscarriages can be attributed to chromosomal abnormalities, up to 40 percent of miscarriages could be due to genetic factors that influence the health of the mother. 

Researchers investigated data from the Danish health registers for 54,394 women with endocrine disease and 312,154 without endocrine diseases born between 1977-1993 who had one or more pregnancies. They discovered a significant correlation between endocrine disease in women and recorded miscarriage, which increased with recurrent pregnancy loss. 

Women with endocrine disease had a 15 percent higher risk of experiencing one miscarriage, a 31 percent higher chance of experiencing two and an 81 percent increased chance of experiencing three. Risk of recurrent miscarriage, with two or three consecutive pregnancy losses, was increased by 87 percent in people with endocrine disease. 

Analysis of family records showed that people with parents with type 2 diabetes had an eight percent increased risk of miscarriage, and those with siblings with the condition had a 13 percent increased risk. 

Authors highlighted that as very early pregnancy loss was not necessarily captured in the data, there was a chance of underdiagnosed miscarriage in both the cohort of this study and the general population they were compared to. 

'I think this is a very interesting study and highlights the familial associations for many medical conditions which originate both from shared genetics and also environmental exposures. This also emphasises the need to encourage people to be more open about disclosing their medical history with relatives in order to help prevent the heartbreak of pregnancy loss amongst family members,' said Professor Adam Balen, professor of reproductive medicine and surgery at Leeds Centre for Reproductive Medicine and Care Fertility Leeds, who was not involved in the research.