One in eight mothers in England is now diagnosed with gestational diabetes, with diagnoses rising by 60 per cent in just five years, according to a major study led by the University of Edinburgh and involving researchers from King's College London.
Published in BMJ Medicine, the study found that rates of gestational diabetes - a condition that develops during pregnancy and can cause serious complications for both mother and baby - increased from around eight per cent of pregnancies in 2018 to more than 12 per cent in 2022.
The sharpest rises were seen among some ethnic minority groups and women living in deprived areas.
Rising maternal age, increasing rates of obesity and improvements in data capture are likely contributors to the growing prevalence of the condition, according to the researchers. They say the findings highlight an urgent need to strengthen maternity services and improve support for women at highest risk.
Gestational diabetes mellitus (GDM) is the most common complication that occurs during pregnancy. It develops when the body can't produce enough insulin to regulate blood sugar levels.
GDM is associated with an increased risk of complications including preterm birth, emergency Caesarean section and babies being born either larger or smaller than expected for their gestational age. It is also linked to long-term health risks for both mothers and their children.
In the study, researchers analysed routinely collected NHS maternity data covering over 2.3 million mothers and around 2.8 million births across 184 hospitals in England between 2018 and 2022.
The highest increases in gestational diabetes were seen among Asian women, where rates reached around 23 per cent, and among women living in the most deprived areas, where they reached around 14 per cent.
The study also found marked inequalities in pregnancy outcomes across ethnic and socioeconomic groups. Black mothers were more likely to experience an emergency Caesarean birth, women living in deprived areas were more likely to give birth preterm, and Asian mothers were more likely to have babies born small for gestational age.
Among these higher-risk groups, a diagnosis of gestational diabetes was associated with a further increase in the risk of preterm birth.
Pregnancy outcomes for women with gestational diabetes are still worse than those for women without gestational diabetes. Further work is required to address how control of blood sugar and timed birth can address the excess of adverse pregnancy outcomes, compared with the general maternity population. Follow-up after birth is also essential, as women with prior gestational diabetes are at increased risk of cardiometabolic disease, including type 2 diabetes mellitus, but also high blood pressure and elevated blood cholesterol, starting within the first year after birth.
Laura Magee, Professor of Women's Health at King's College London and co-investigator on the study
The study also found that changes to gestational diabetes screening introduced during the COVID-19 pandemic did not meaningfully affect overall trends in diagnosis. Experts say the rise in cases reflects broader underlying changes rather than changes in testing practice.
This the first time we have managed to estimate the number of women with gestational diabetes in the UK. The rising number of women being diagnosed is concerning and impacts on maternity services delivery which are already challenged.
Rebecca Reynolds, Professor of Metabolic Medicine at the University of Edinburgh and lead author of the study
"Importantly, gestational diabetes also increases risk of future type 2 diabetes and cardiovascular disease, so better preventative measures are needed to help support these women post partum," added Professor Reynolds.
Dr Sonya Babu-Narayan, Clinical Director at the British Heart Foundation, said: "Big data research studies like this, which can now analyse millions of healthcare records, are uncovering a concerning rise in conditions which raise people's chances of having a future heart attack or stroke. Gestational diabetes often goes away after pregnancy, but it can increase women's risk of future cardiovascular disease. Healthcare professionals who want to fully understand people's risk of heart attack and stroke should routinely ask women about risk factors unique to them, such as diabetes or high blood pressure in pregnancy - even if that pregnancy was decades earlier. If you are a woman who has had diabetes or high blood pressure during pregnancy, it is especially important to attend health checks when invited."
The study also involved researchers from the University of Glasgow, University of Warwick and the HDRUK Diabetes Data Catalyst, a partnership between British Heart Foundation Data Science Centre, Diabetes UK and Health Data Research UK. It was funded by the British Heart Foundation.
