UPBEAT: Diet and exercise for women who are obese in pregnancy

Professor Lucilla Poston, Dr Annette Briley, Dr Dharmintra Pasupathy, Mr Paul Seed, the UPBEAT Consortium

Tommy’s has supported the largest ever clinical study of obese pregnancy. This trial has given us resources that we can use far into the future to look at how obesity affects the health of mothers and babies during pregnancy and beyond.

This study is now complete

UPBEAT (the UK Better Eating and Activity Trial) is the largest ever clinical study looking at obese pregnant women. Women who are obese during pregnancy are more at risk of complications such as diabetes and pre-eclampsia. We wanted to see if helping women get healthier during pregnancy could stop some of these.

Changes in diet in pregnancy

During pregnancy, women made changes to their lifestyle focused on eating foods with a low glycaemic index (GI) and doing more physical activity.

GI measures the effect of a food on a person’s blood sugar level. Eating foods with a low GI generally means that sugar is released more slowly into the blood. As there is no sudden 'spike,' this means that it should be easier for the body to maintain its blood sugar levels.  

We hoped that helping women to control their blood sugar better would stop them from developing diabetes during pregnancy, and in turn help stop babies from growing too large.

Diabetes, and babies that are large for their gestational age (LGA) can both cause problems such as difficult labour, and a higher risk of the baby getting diabetes when it grows up. So, stopping these before they start would be the best way of preventing other risks for both mother and baby.

Big changes in diet and exercise are possible

Over 1,500 obese pregnant women took part in UPBEAT. The women were randomly sorted into two groups: the 'intervention' group made changes to their diet and lifestyle, while the 'control' group didn’t.

The results from the study were clear: the changes didn’t decrease the number of women developing diabetes or giving birth to babies that were too large. They also didn’t affect the number of women suffering from other pregnancy complications.

However, women who adopted the changes ate far less carbohydrates and saturated fat, and did a lot more physical activity than women who did not. They also gained less weight and body fat during pregnancy.

Importantly, this study has shown that the UPBEAT intervention can lead to big changes in diet and physical activity in obese pregnant women.

More research into the effects of early diet on babies

We are carrying on looking at UPBEAT mothers to see if women stick with the changes they made. Many of these follow-on studies are part of the EarlyNutrition project, a multinational EU funded study looking at the effects of early nutrition on later life. Already, we’ve found that mothers who improved their diets have carried on eating more healthily 6 months after birth.  

More significantly, we are now undertaking research to find out if these changes during pregnancy have longer-term benefits for mothers and babies. These might include lowering the risk of childhood obesity and giving babies healthier hearts.

Finally, UPBEAT has given us a great resource to use in the future. As well as following up UPBEAT participants, we now have a bank of biological samples that we can use to look at the ways that diseases work at a cellular level.

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Tommy's funds research across the UK investigating the reasons for pregnancy complications and loss. We can keep you updated on our research news. If you're interested in being kept updated about our research and news from Tommy's, click here.

UPBEAT trials


This study takes place in a Tommy's centre and is funded by Tommy's, the National Institute for Health Research, Chief Scientist Office Scotland, and Guy's and St Thomas' Charity

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