UPBEAT: Diet Plus Exercise Doesn’t Prevent Gestational Diabetes
July 17, 2015A behavioral intervention that combines diet and exercise did not prevent gestational diabetes (GDM) or large-for-gestational age (LGA) babies in obese pregnant women, according to results from one of the largest randomized controlled trials to look at this issue.
Results from the UK Pregnancies Better Eating and Activity Trial (UPBEAT) were published online in the Lancet Diabetes and Endocrinology on July 10, 2015.
“While the [study] found that obese women who take part in a health-trainer–led program will improve their diet and take more exercise, the benefits of these changes are unlikely to be adequate to reverse the insulin resistance that leads to gestational diabetes,” lead author Lucilla Poston, PhD, from the division of women’s health at King’s College London, United Kingdom, told Medscape Medical News.
Results from the UPBEAT study add to a growing body of evidence that lifestyle interventions may not be enough to fend off GDM in obese pregnant women, according to Dr Poston.
A recent pilot study for the European Vitamin D and Lifestyle Intervention for GDM Prevention (DALI) trial similarly found that an intervention combining diet and exercise did not reduce measures of blood glucose control, although that study could not assess differences in GDM incidence.
Dr Poston said that the focus therefore needs to shift toward improved screening and treatment for GDM. Research is also needed into early-pregnancy risk-assessment tests. Such tests could reduce the “substantial” healthcare costs related to obesity in the United Kingdom, she pointed out.
UPBEAT: One of First Intervention Trials to Assess Gestational Diabetes
Obesity during pregnancy is currently highest in high-income countries — affecting about 25% of women in the United Kingdom and 34% of women in the United States — and increases the risk for insulin resistance and GDM, which in turn increases the risk for stillbirth, LGA babies, and other birth complications. Children born to mothers with GDM also have a higher risk of metabolic disease in later life.
There have been many clinical trials in obese pregnant women, primarily of behavioral interventions addressing diet and physical activity, Dr Poston and colleagues note.
“However, most trials have been underpowered for clinical outcomes such as gestational diabetes, focusing instead on restriction of gestational weight gain.” Nevertheless, systematic reviews of these mostly small trials have suggested the potential for prevention of gestational diabetes in women with obesity by behavior-change interventions in pregnancy, they note.
The UPBEAT trial took place between March 2009 and June 2014 at prenatal clinics in eight hospitals in multiethnic inner-city neighborhoods in the United Kingdom. The study included obese pregnant women with a mean body mass index (BMI) of 36.3 kg/m2, 26% of whom were black.
The researchers randomized women to a behavioral intervention plus standard care (n = 783) or standard prenatal care (n = 772). Women in the intervention group participated in health-trainer–led sessions for 1 hour once per week for 8 weeks. These women also received handbooks with recommended foods, recipes, and physical activities, as well as DVDs with exercises safe for pregnancy, a pedometer, and a log book for recording goals.
Women took an oral glucose tolerance test (OGTT), and GDM was diagnosed on the basis of criteria from the International Association of Diabetes in Pregnancy Study Group (IADSPG), also adopted by the World Health Organization (WHO).
Among 651 (84%) women who took an OGTT test in the standard-care group, 172 (26%) developed GDM, compared with 160 (25%) of 629 (80%) women who took an OGTT in the intervention group (risk ratio, 0.96; P = .68).
Of 751 babies born in the standard-care group, 61 (8%) were LGA, compared with 71 (9%) of 761 babies born in the intervention group (risk ratio, 1.15; P = .40).
Using the IADPSG/WHO criteria for diagnosing GDM — more stringent than criteria currently used in the United Kingdom — may have resulted in the lower-than-expected incidence of LGA babies seen in both groups, compared with women with the same BMI treated in the general population, Dr Poston pointed out.
“[W]e think this was because of the better diagnosis and treatment of GDM [using the IADPSG/WHO criteria],” she explained.
Intervention Could Be of General Health Benefit
However, compared with the standard-care group, the intervention group did show improvements in dietary glycemic load, fat intake, activity levels, and a modest decrease in body fat and weight gain (about half a kilogram less than the standard-care group).
Although the intervention did not prevent GDM, it could be of “general health benefit,” Dr Poston mentioned.
“All obese women should try to improve their diet and modestly increase their physical activity. This may be best achieved by attending weekly sessions for pregnant women with a professional lifestyle ‘coach,’ ” Dr Poston counseled.
“Overweight women would not normally be tested for diabetes, but the dietary and physical-activity advice would the same,” she added.
In a linked comment, Shakila Thangaratinam, PhD, MRCOG, professor in maternal and perinatal health at Queen Mary University of London, United Kingdom, mentions that the National Institute for Health and Care Excellence (NICE) guidelines recommend referral to a dietician for obese pregnant women but do not recommend regular weighing during pregnancy.
“Based on the UPBEAT study ﬁndings, a change in current UK guidelines is not needed,” she writes. “Women should be informed that although a healthy diet and lifestyle could minimize weight gain in pregnancy, there is no robust evidence for improvement in outcomes such as gestational diabetes or large-for-gestational-age babies.”
Reducing excess weight gain during pregnancy, however, could decrease weight retention after pregnancy and decrease the risk of obesity at the start of future pregnancies, she stresses.
“Prevention of obesity needs to be prioritized equally with efforts to reduce complications in obese pregnant women,” Dr Thangaratinam emphasizes.
The research was funded by the UK National Institute for Health Research. Dr Poston reports a research grant from Abbott Nutrition, outside the submitted work. Disclosures for the coauthors are listed in the article. Dr Thangaratinam reports being chief investigator of a National Institute for Health Research project that receives data contribution from the UPBEAT study.
Lancet Diabetes Endocrinol. Published online July 10, 2015. Article, Editorial