A call to increase physical activity among women of reproductive age: is it possible?

Abstract

Gestational diabetes (GDM) is an increasingly commonpregnancy complication.Womenwith GDMare at extremely high risk of developing diabetes, especially in the first 5 years after delivery. In their article on the Nurses’ Health Study (NHS) II in this issue of JAMA Internal Medicine, Bao et al1 found that following a GDM pregnancy, increasing physical activity levelswere associatedwith a reduced risk of progression from GDM to diabetes. This findinghighlights the importance of developing effective behavioral interventions to increase physical activity after a GDM pregnancy. A randomized clinical trial of one such behavioral intervention, the Diabetes Prevention Program (DPP),2 found that among overweight or obese women with impaired glucose tolerance, an intensive lifestyle intervention,whichaimedtoachieveweight reduction throughbothphysical activity anda low-fat diet, reduced the risk of developing diabetes by 58%.3 However, the subgroup of womenwith a history of GDM—approximately 8 yearsyounger thanwomenwithoutahistoryofGDM—was less likely to adhere to the lifestyle intervention, less successful at sustaining increases inphysically activity, and lost lessweight thanwomenwithout ahistory ofGDM.3These subgroup findings likely signal the challenges faced by women with young families who are struggling to engage in self-care behaviors, suchas increasingtheirphysicalactivity levels,amidst thecompeting demands of work and family. More data on physical activity during the early postpartumperiod are needed amongwomenwith GDM. In addition to the challenges of early parenthood faced bywomenwith a recent diagnosis of GDM, it is possible that younger women withGDMmaynotbeas awareof their diabetes risk and therefore may have less motivation for changing lifestyle behaviors.WomenintheDPPhadpregnanciesapproximately12years before study enrollment, leavingunanswered the question of whether the lifestyle intervention could have been more effective closer to the time of diagnosis and delivery. Unfortunately, Bao et al1 did not address how soon after a GDM pregnancywomen’sphysicalactivity levels increased. Itwouldhave been useful to know atwhat point postpartumwomenwith a pregnancycomplicatedbyGDMaremotivated to increase their physically activity levels.A recent feasibility randomizedclinical trial of a prenatal and postpartum lifestyle intervention, similar to theDPPbut deliveredby telephone anddesigned to help women lose weight during the first year postpartum, found that the lifestyle intervention was effective in reducingdietary fat intakebutwasnot effective in increasingphysical activity levels.4 While measurement error may have contributed to these null findings, further research is needed in this area. A pilot study randomized 49 women with a recent history of GDM (within 3 years) to a 13-week intervention of a web-based pedometer program or a control condition, which included a letter about diabetes risk reduction.5 The investigators found no difference in physical activity between the groups. Taken together, these studies suggest that more intensive interventionsmay be needed to increase physical activity in GDMwomen during the postpartum period. There is a clear need for intervention strategies to help postpartum womenidentifyandovercomebarriers inorder to increase their physical activity. There are several ongoing randomized trials in theUnited States testing lifestyle interventions that start during pregnancy and continue through the first year postpartum for womenwithGDM.One isapragmatic cluster randomizedclinical trial including 2320 women6 (clinicaltrials.gov identifier: NCT01344278), and for theother, randomizationof350women occurs at the individual level (clinicaltrials.gov identifier: NCT01489163). Both are testing the effectiveness of a DPPderived print and telephone lifestyle interventions compared with usual care practices alone in helping women lose weightduring the firstyearpostpartum.Both interventionsencourage women to increase their levels of moderate to vigorous intensity physical activity up to 150 minutes per week. Similar trials are also occurring outside of the United States. Since 2005, the Tianjin Gestational Diabetes Prevention Program has randomized 1180 women with GDM to either a behavioral intervention group or a comparison group to evaluate the effectiveness of a lifestyle intervention in preventing diabetes.7 Women in the intervention group are advised to engage in moderate to vigorous physical activity 5 days a week. It will be critical to see if these early postpartum interventions are effective in increasing physical activity levels in women with GDM. In the meantime, the article by Bao et al1 provides evidence of a hopeful message for women with GDM that if they can increase their physical activity, they may potentially reduce or delay their risk of developing diabetes. Even as health systems and public health programs find ways to help young postpartumwomen increase their physicalactivity levels, thechallenges inherentduring theearlypostpartum periodmake it necessary to design lifestyle interventions that start before pregnancy.Womenof reproductive age thus represent aparticularly important group to target for lifestyle interventions designed to increase physical activity and achieveanappropriateweight.Beingoverweightorobeseduring pregnancy is associated with several perinatal complicaRelated article page 1047 Research Original Investigation Physical Activity & Sedentary Behavior in Diabetes