Obese and pregnant? Testing for gestational diabetes makes pregnancy safer

At the Tommy’s London Centre we have just completed UPBEAT, an important study in obese mums-to-be. The results have been published in the journal The Lancet Diabetes and Endocrinology.

By Professor Lucilla Poston, Tommy's @ London

At the Tommy’s London Centre we have just completed UPBEAT, an important study in obese mums-to-be. The results have been published in the journal The Lancet Diabetes and Endocrinology.

Obesity increases the likelihood of gestational (pregnancy-related) diabetes and of having babies that are too large, which can lead to difficulties at birth.

We wanted to see whether a programme of diet and lifestyle advice given by a hospital health trainer could help prevent gestational diabetes. 

The dietary advice recommended more low-glycaemic index foods and less saturated fat. It didn’t focus on reducing the mother’s weight gain. Participants also had health trainer sessions (eight visits in all, once a week).

Over 1,500 pregnant women from cities in London and Scotland took part. They had an average Body Mass Index (BMI) of 36. Half were allocated to the lifestyle programme on top of normal antenatal care and the other half just had normal antenatal care.

The participants who had the lifestyle programme showed changes to their diet and increased the time they spent walking every day.

This was linked to less weight gain and lower body fatness - all positive results.

The programme wasn’t enough to prevent gestational diabetes nor were there fewer babies born too large compared to participants who just had normal antenatal care.

However, overall there many fewer large babies in the participants than we had expected. This is likely to be a result of the study testing all women for gestational diabetes and treating it (using diet and exercise, and medication if needed).

The study used a new and very sensitive test for diabetes, one which has recently been recommended by the World Health Organisation. Using this test, one in four obese mums to-be were found to have gestational diabetes. In many cases it was mild diabetes, but nevertheless it shows the extent of the problem.

If you are pregnant with a BMI of 30 or over we recommend you make sure your midwife or doctor offers a test for diabetes.

The test is usually done between 24 and 28 weeks of pregnancy. It is recommended by NICE but unfortunately a lot of women fall through the net and are not tested. If you have a BMI of 30 or over, make sure you bring it up if you are not offered the test. 

We also recommend that women who are overweight should try to lose weight before getting pregnant if possible.

If you are found to have gestational diabetes, your treatment is likely to start off with a diet like the UPBEAT diet, and maybe some tablets or insulin. This should reduce the risk of your having a baby born too large, and lots of other complications too.