Pregnancy exercise and nutrition with smartphone application support a randomized controlled trial

OBJECTIVE: To evaluate the effect of a healthy lifestyle package (an antenatal behavior change intervention supported by smartphone application technology) on the incidence of gestational diabetes mellitus (GDM) in overweight and obese women. METHODS: Women with body mass indexes (BMIs) 25‐ 39.9 were enrolled into this randomized controlled trial. The intervention consisted of specific dietary and exercise advice that addressed behavior change supported by a tailor‐designed smartphone application. Women in the control group received usual care. The primary outcome was the incidence of GDM at 28‐30 weeks of gestation. To reduce GDM from 15% to 7.2%, we estimated that 506 women would be required to have 80% power to detect this effect size at a significance of .05, that is, 253 in each group. RESULTS: Between March 2013 and February 2016, 565 women were recruited with a mean BMI of 29.3 and mean gestational age of 15.5 weeks. The incidence of GDM did not differ between the two groups, 37 of 241 (15.4%) in the intervention group compared with 36 of 257 (14.1%) in the control group (relative risk 1.1, 95% CI 0.71‐1.66, P5.71). CONCLUSIONS: A mobile health‐supported behavioral intervention did not decrease the incidence of GDM.