The study published today in PLOS ONE, led by Professor Lucilla Poston at King’s and using data collected during the UK Pregnancies Better Eating and Activity Trial (UPBEAT), uncovers evidence of more than one pathway to gestational diabetes in obese women. This discovery could lead to personalised treatment plans and tests to better predict the condition.

Gestational diabetes develops when the body is unable to control blood sugar levels. The condition affects approximately 30 in every 100 pregnant obese women in the UK. These women have raised blood sugar (hyperglycaemia) and have an increased risk of an oversized baby with complications during labour and delivery. A rare but serious consequence of the illness includes stillbirth.

Previous studies have suggested the cause of the condition in obese women is excessive insulin resistance – when cells in the body do not respond properly to insulin - but the findings from this study suggest that this is not the only cause.

The study, funded by Diabetes UK and Tommy’s, looked at metabolic phenotypes from the early, mid and late stages of pregnancy from 71 women who developed gestational diabetes in mid pregnancy. The data was analysed according to the treatment received to manage their hyperglycaemia – either diet, metformin (a medicine to treat type 2 diabetes) or insulin. When researchers studied their blood markers, they found that even in early pregnancy, many weeks before diagnosis of gestational diabetes, there were differences in blood markers between treatment groups.

The most marked difference was found between those women treated with insulin, who exhibited a clear insulin resistant profile, whereas women treated with diet showed a non-insulin resistant profile. This suggests a different pathway to gestational diabetes, possibly through insufficient production of insulin. Treatment choice for affected women is generally based on how high a woman’s blood sugar is. The findings hint that treatment choice may be unintentionally influenced to some degree by the underlying cause of the disorder. This is the first study to analyse the metabolic profile of obese women with gestational diabetes according to the three conventional types of treatment.

More research is needed to confirm the findings, but this could lead to care that is specific for the type of gestational diabetes that a woman develops. Eventually, this could generate tests that could provide more accurate prediction, diagnosis and enable targeted treatment for gestational diabetes.