Obese women are 3-6 times more likely to develop diabetes during pregnancy than women who have a healthy weight. Diabetes can hurt both mother and baby, and increases the likelihood of stillbirth and premature birth, as well as the risk of diabetes and obesity when the baby grows up. This means that it is vital to be able to tell early which women are more likely to develop diabetes during pregnancy. We can then try and stop it before it happens, or treat it as early as possible.
Studies like UPBEAT have tested if changing the diets and lifestyles of obese pregnant women could help lower the risk of diabetes. The results were unexpected: the risk of diabetes stayed the same. This means it is even more important to find out how and why some women get diabetes, while others don’t. We are looking for changes in certain “biomarkers” in the blood before and during diabetes in over 1,500 women who took part in UPBEAT. These could help us to understand how the disease works, and how to tell which women are most at risk.
'Biomarkers' are simply substances made by the body that can give us clues about how our bodies work. They are very useful for understanding disease: we can look for markers that are different in people who have a certain illness. Scientists can then use this information to help predict, and hopefully treat, the problem.
Over the last 12 months, researchers supported by Tommy’s have been looking at blood samples over the course of pregnancy from women in the UPBEAT trial. They have found significant changes in blood samples from women who go on to develop diabetes compared to those who don’t. These changes in blood samples were evident at around 17 weeks of pregnancy – much earlier than the time of gestational diabetes diagnosis at the end of the second trimester.
Researchers also found that weight gain during pregnancy had less impact than early pregnancy BMI on gestational diabetes risk. This suggests that interventions to prevent gestational diabetes in obese women should focus on pre-conception and early pregnancy rather than weight gain during pregnancy.
The results from this study strengthen our theory that there are complex processes that lead to gestational diabetes in obese pregnant women. However, we have uncovered important clues as to why some obese women develop diabetes in pregnancy, while other don’t.
We hope to explore these processes in future studies, to help us find out which women are more likely to suffer from it.
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