Babies born to mothers who were obese during pregnancy are three times more likely to develop type 2 diabetes in later life, according to research funded by Tommy's and the UK Medical Research Council. 

The study, published in the journal Diabetologia, also found that being overweight, but not obese, during pregnancy increases the risk of diabetes in the child by almost half. The findings add to the list of health problems linked to offspring of obese pregnant women, which also include heart disease, behavioural problems and early death.

Researchers say public health interventions are urgently needed to help women who may be planning pregnancies to maintain a healthy weight. 

The cycle of ill health caused by obesity damages future generations

Tommy's Chief Executive, Jane Brewin, said: ‘This research adds to the growing body of evidence that maternal health before, as well as during, pregnancy affects the health of children into the future. The cycle of ill-health caused by obesity is particularly damaging to future generations.

"We need wider awareness of the importance of health before conception as well as supportive and accessible programmes that help women who have a high BMI to lose weight before pregnancy and manage their weight during pregnancy. This would return dividends with a healthier future generation as well reducing the many pregnancy complications associated with obesity."

The team studied birth records from more than 100,000 people born between 1950 and 2011 in the Aberdeen area and linked them with the national register for diagnosed diabetes in Scotland.

Figures revealed around one-quarter of women were overweight during pregnancy over the 60-year period. One in ten were obese, with a body mass index (BMI) greater than 40.

The proportion of obese mothers increased five-fold from around one in 30 during the 1950's to almost one in six between 2000 and 2011.

Shared lifestyle between mother and child could contribute to the risk

Children from mums who were overweight or obese during pregnancy were more likely to develop either type of diabetes in their lifetime – type 1 or type 2 – the study revealed. Risks were higher for type 2 diabetes.

The researchers did not look at BMI of the offspring, or other lifestyle factors such as diet and exercise that are known to increase risk of type 2 diabetes. They say shared lifestyle between mother and child could contribute to the development of the condition.

Further studies are needed to better understand how a high BMI during pregnancy leads to diabetes in offspring. One theory is that it may cause an adverse environment in the womb, where high levels of sugar and insulin trigger metabolic processes in the fetus that lead to diabetes.

Around half of all women of childbearing age are overweight or obese in the UK, recent figures suggest. The researchers say there is an urgent need to establish effective interventions to prevent obesity during pregnancy.

Professor Rebecca Reynolds, of the Tommy’s Centre for Maternal and Fetal Health at the University of Edinburgh, said: "We found an increased risk of developing diabetes in children born to obese mothers, which was not linked to sociodemographic factors. Our findings underline the urgent need to find ways of helping women plan for pregnancy by optimising their health – including reaching and maintaining a healthy weight."