A diet and exercise regime for high-risk obese pregnant women is effective in promoting a healthy lifestyle but it does not prevent gestational diabetes, new research has found.
According to the study led by King’s College London, programmes promoting healthy behaviour are unlikely to be effective in preventing gestational diabetes in obese women.
They suggest that instead, resources should be directed towards better screening and treatment, including the use of a more stringent threshold for diagnosis.
Obesity rates are highest in developed countries, affecting 25% of women in the UK and 34% of women in the US. Obesity is a risk factor for complications in pregnancy, especially gestational diabetes and large-for-gestational-age delivery (LGA).
Previous studies have suggested that lifestyle intervention programmes might help reduce the risk of gestational diabetes in obese pregnant women, but this is the first large scale trial to test the effects of an intensive intervention in the UK and the rest of the world.
The randomised UPBEAT study recruited over 1,500 women from eight inner city antenatal services providing care to multi-ethnic populations of generally high socioeconomic deprivation across the UK.
Half the women, 772, were placed in a control group and given standard antenatal care and advice, whilst the other half, 783, were assigned to eight weekly, health trainer-led sessions.
Participants were given a handbook with recommended foods, recipes and physical activity along with a DVD of an exercise regime safe for pregnancy, a pedometer and a log book for recording their weekly goals.
Exercise focused on increasing the amount of walking at a moderate intensity, and the women were advised to adopt a healthier diet by swapping carbohydrate rich foods for those with a lower glycaemic index and limiting their saturated fat intake.
All the women took a standard oral glucose tolerance test, but researchers used more stringent World Health Organisation recommended criteria, also known as IADSPG criteria, to diagnose gestational diabetes and implement treatment accordingly.
Overall, 26% of participants were diagnosed with gestational diabetes, but the study found no significant difference between the standard and intervention groups. LGA infants made up 9% of the whole trial cohort, but again, no difference was observed between standard and intervention groups.
However, the intervention led to other changes such as a lower glycaemic load and fat intake along with higher levels of activity which were associated with reductions in pregnancy weight gain and reduced body fat.
Furthermore, researchers predicted that 17% of children would be LGA, but found levels to be closer to normal population levels, typically around 10%, which they believe to be due to the greater number of women diagnosed and treated for gestational diabetes using the WHO guidelines.
‘Our study shows that an intensive diet and exercise regime alone cannot help reduce the risk of developing gestational diabetes in obese women. However, using a more stringent diagnostic test for gestational diabetes meant we picked up more cases,’ said Professor Lucilla Poston, lead author from the Division of Women’s Health at King’s College London.
‘We believe the greater number of women treated as a result of this test may explain why our study found a lower than anticipated incidence of LGA infants in all women. This has implications for the diagnosis of gestational diabetes in the UK,’ she explained.
‘Whilst the intervention did not prevent gestational diabetes, the UPBEAT study provides a new and effective strategy to improve diet and physical activity in obese pregnant women adoptable in a UK healthcare setting. We are now following the mothers and children from this cohort to see whether changes in the mothers’ diet and activity are sustained and have an effect on their health and that of their offspring,’ she added.
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