Gestational diabetes is becoming increasingly common in England, affecting more than one in eight pregnancies by 2022, according to a large analysis of National Health Service maternity records. The study, published in BMJ Medicine, found that the proportion of pregnancies involving gestational diabetes mellitus (GDM) rose from approximately 8 per cent in 2018 to more than 12 per cent four years later. That represents an increase of about 60 per cent in five years, placing additional pressure on maternity services already managing increasingly complex pregnancies.
Gestational diabetes develops when the body cannot produce or use sufficient insulin to maintain normal blood glucose levels during pregnancy. Insulin is a hormone produced by the pancreas that allows glucose to move from the bloodstream into cells, where it is used for energy. Pregnancy naturally increases insulin resistance, partly because hormones produced by the placenta interfere with insulin action. In most women, the pancreas compensates by producing more insulin. When it cannot meet this demand, blood glucose rises and GDM develops.
Although gestational diabetes often resolves after childbirth, elevated glucose levels during pregnancy can affect both mother and baby. Excess glucose crosses the placenta, prompting the fetal pancreas to produce additional insulin. This can encourage accelerated growth and increase the likelihood of a baby being large for gestational age, although impaired placental function and other biological factors can also be associated with restricted growth. GDM has been linked to preterm birth, emergency Caesarean delivery and a range of complications requiring additional monitoring before and after birth.
Researchers analysed routinely collected NHS data from more than 2.3 million mothers and approximately 2.8 million births recorded across 184 hospitals in England between 2018 and 2022. The scale of the dataset allowed the investigators to examine diagnosis patterns across ethnic and socioeconomic groups, while also assessing pregnancy outcomes. As an observational study, the analysis could identify associations and changes over time but could not establish that any single factor directly caused the increase in diagnoses.
The highest recorded rates were found among Asian women, reaching approximately 23 per cent by 2022. Rates also rose among women living in the most deprived areas, reaching about 14 per cent. These differences reflect the interaction of multiple influences, including genetic susceptibility, body composition, access to healthcare, diet, social conditions and the prevalence of pre-existing metabolic risk factors. The researchers also noted that increasing maternal age and rising obesity rates are likely to have contributed to the overall trend.
The analysis revealed broader inequalities in pregnancy outcomes. Black mothers were more likely to experience emergency Caesarean birth, while women living in deprived areas had a higher likelihood of preterm delivery. Asian mothers were more likely to have babies classified as small for gestational age. In groups already facing elevated risks, a diagnosis of gestational diabetes was associated with a further increase in the likelihood of preterm birth, highlighting the importance of early identification and coordinated antenatal care.
The researchers found no meaningful change in the overall upward trend that could be attributed to altered screening procedures during the COVID-19 pandemic. Screening pathways were modified in some areas during the pandemic to reduce hospital visits and limit infection risks, raising concerns that changes in testing could have distorted national figures. Instead, the findings suggest that the increase reflects deeper population-level changes, although improvements in the completeness and accuracy of healthcare data may also have increased the number of recorded diagnoses.
The consequences of GDM can extend well beyond pregnancy. Women who develop the condition face an increased long-term risk of type 2 diabetes, hypertension and cardiovascular disease, including heart attack and stroke. Their children may also have a greater lifetime susceptibility to obesity and abnormal glucose regulation. Rebecca Reynolds, Professor of Metabolic Medicine at the University of Edinburgh, said the rising number of diagnoses would affect maternity service delivery and called for stronger preventive measures and better postnatal support for women who have had gestational diabetes.
The British Heart Foundation’s Clinical Director, Dr Sonya Babu-Narayan, said that gestational diabetes should be considered part of a woman’s long-term cardiovascular history, even if it occurred decades earlier. She urged women who have experienced diabetes or high blood pressure during pregnancy to attend routine health checks when invited. The study involved researchers from King’s College London, the universities of Glasgow and Warwick, and the HDRUK Diabetes Data Catalyst, a partnership involving the British Heart Foundation Data Science Centre, Diabetes UK and Health Data Research UK. It was funded by the British Heart Foundation.
Subject of Research: People
News Publication Date: 3 August 2026
Web References: https://doi.org/10.1136/bmjmed-2025-002412
References: BMJ Medicine, DOI: 10.1136/bmjmed-2025-002412
Keywords: gestational diabetes, pregnancy, maternal health, NHS, maternity services, health inequalities, cardiovascular disease, type 2 diabetes, preterm birth, emergency Caesarean, ethnic disparities, public health
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