Rise in autoimmune disease prevalence in pregnant women, finds study

By Rebecca Jenkins

The prevalence of autoimmune diseases is rising in pregnant women, a large retrospective cohort study finds.

Autoimmune diseases were known to disproportionately affect women, particularly those in the reproductive age group, with about 80% of some types of autoimmune conditions occurring in women, UK researchers wrote in The Lancet Rheumatology.

To quantify the burden of 17 autoimmune diseases during pregnancy, the researchers analysed UK registry data from more than five million pregnancies in women aged 15 to 49 years between 2000 and 2021.

Overall, there was an increase in prevalence of autoimmune diseases from 3.5% in 2000 to 4.7% in 2021.

Of the diseases studied, psoriasis had the highest prevalence throughout the study period, followed by inflammatory bowel disease and rheumatoid arthritis in 2000 to 2010 and type 1 diabetes and inflammatory bowel disease in 2010 to 2021. The steepest increase was seen with Hashimoto’s thyroiditis, followed by coeliac disease, Graves’ disease and type 1 diabetes.

Higher odds of being diagnosed with an autoimmune disease were associated with White ethnicity, living in less deprived areas, higher body mass index, older maternal age and smoking, although trends varied between diseases, the researchers found.

‘This is one of the first studies to describe trends in the prevalence of such a wide range of autoimmune diseases in pregnancy,’ the researchers wrote.

‘Although the burden of each disease is relatively small, the overall prevalence of autoimmune diseases is important, highlighting the need to establish adaptable health policies and allocate resources effectively to address the diverse needs associated with autoimmune diseases in this population.’

Dr Antonia Shand, Obstetrician and Research Fellow at  The University of Sydney, said the findings were likely to be generalisable to Australia, noting a higher prevalence than an Australian study she coauthored that found about 2.5% prevalence of autoimmune diseases in pregnant women.

She told Medicine Today that as this was an epidemiological study it was difficult to know whether there was causation or association with highlighted risk factors.

‘Interestingly, there is a reported increase associated with higher socioeconomic status – but the authors hypothesise that these women may be more likely to have access to health care,’ she said.

Dr Shand said ideally women with autoimmune diseases would have planned pregnancies, at a time where there was good disease control, with a plan for any potentially teratogenic medications to be changed if necessary.

Care from a multidisciplinary team including obstetricians, physicians, midwives and other specialists and allied health was very important.

‘It is important that women have accurate information about medicines in pregnancy, as disease control is crucial, and stopping medicine that is controlling the disease may actually not improve outcomes,’ she said.

In addition, some women with autoimmune diseases might mistakenly believe they were infertile, so conversations about contraception, preconception care and pregnancy planning were especially important for women with health conditions.

‘As part of good preconception care, it is good to discuss the effect of the health condition on the pregnancy, and the pregnancy on the health condition,’ Dr Shand said.

‘It is also important to discuss general health such as smoking, alcohol, folate [levels] and vaccinations.’

Lancet Rheum 2025; https://doi.org/10.1016/S2665-9913(25)00039-6.