More women who are having children have been diagnosed with an autoimmune condition since the millennium. But why?
Autoimmune diseases are conditions in which the immune system mistakenly attacks the body’s healthy cells and tissues, treating them as if they were harmful invaders, such as viruses or bacteria. Common autoimmune diseases include Rheumatoid Arthritis (RA), Lupus, and Psoriasis.
In a new paper, researchers involved in the MuM-PreDiCT project, a comprehensive study aimed at understanding the prevalence and impact of autoimmune conditions in pregnant women, run by the University of Birmingham and funded by the Medical Research Council, have found a 4.7% increase in expectant mothers beginning pregnancy with autoimmune conditions.
The findings are published in Lancet Rheumatology.
This pioneering study unveils the correlation between pregnant women and autoimmune diseases
The researchers analysed electronic healthcare records (CPRD) from 2000 to 2021, including over 5.1 million pregnancies in more than 2.8 million women. They examined the prevalence of 17 autoimmune diseases in pregnancies of women of reproductive age. The team applied logistic regression to estimate odds ratios, describing the relationship between women’s characteristics (age, ethnicity, deprivation, BMI, smoking status, and gravidity) and other health conditions that coexist with the autoimmune diseases, known as comorbidities.
Dr Megha Singh from the University of Birmingham and lead author of the study said: “This is the first time that this kind of study has been done, showing that there is a rise in autoimmune conditions in women that are becoming pregnant. We examined a wide range of autoimmune conditions, unlike any study previously conducted, and we found that these conditions, by and large, affect women. Previous studies have shown an overall increase in autoimmune conditions. As a result, these findings are not surprising but are crucial for public health.
“Our project is all about understanding how to support women during pregnancy who are managing medical conditions, often co-morbidly, and this data gives us a much better idea about the scale of autoimmune conditions for expectant mums.”
Psoriasis is the most common autoimmune disease
Out of more than 5.1 million pregnancies, 185,208—occurring in 100,655 women—were affected by a diagnosed autoimmune condition. The combined prevalence of 17 autoimmune diseases increased from 3.5% in 2000 to 4.7% in 2021, with psoriasis consistently being the most common. The steepest increases were observed in Hashimoto’s thyroiditis, coeliac disease, Graves’ disease, and type 1 diabetes.
Women from less deprived areas had higher odds of autoimmune disease, while minority ethnic groups, particularly Black and Asian women, had lower rates compared to white women. Ex-smokers, women with multiple pregnancies (especially five or more), and those with coexisting metabolic or mental health conditions (like type 2 diabetes, hypertension, anxiety, and depression) also had significantly higher odds of having an autoimmune disease during pregnancy.
Dr Francesca Crowe, senior author from the University of Birmingham of the paper, said: “There are likely to be a combination of factors driving the increase in autoimmune condition diagnoses before pregnancy, including different factors among groups of people. An awareness of conditions and differential access to healthcare may be involved, and it is very likely, therefore, that the numbers we are seeing under report the real scale of women’s health in pregnancy.”
Prof Krish Nirantharakumar, corresponding and co-author from King’s College London, said: “This important study will aid clinicians and policymakers to redefine existing care- pathways and plan future health services for pregnant women with autoimmune conditions to achieve better outcomes for mums and their babies.”
