A Cluster RCT of an Internet-Based Programme to Promote Activity and Reduce Postpartum Calorie Intake in Poor Hispanic Women

When I read the introduction and methods section of a research paper I often try to guess the result before I read on. In the case of the paper above [1] I guessed a null result. I guessed wrong. In this cluster RCT (12 clusters, 371 patients), a carefully designed and piloted internet-based intervention to nudge women to healthy living reduced mean mass by a statistically significant 2.3kg compared to standard care. There was no effect on exercise as assessed by a pedometer. The authors express surprise that there was ‘no’ reduction in calorie intake, but they over-interpret this finding. The variance in measured calories was very wide and the p-value was 0.06. They make the mistake of reifying the 95% limits on the confidence interval.

The 2.3kg mean intervention effect may strike some as nugatory. However, a relatively small reduction in mass can have a worthwhile metabolic and health effect, as we showed in a study of liver function tests.[2] Postpartum weight loss is important because it is associated with long-term obesity, is largely truncal, and increases risk in any subsequent pregnancy. Dr Ponnusamy Saravanan from CLAHRC WM is collaborating with Prof Kamlesh Khunti (Director of CLAHRC East Midlands) in tackling the problem.

— Richard Lilford, CLAHRC WM Director


  1. Phelan S, Hagobian T, Brannen A, et al. Effect of an Internet-Based Program on Weight Loss for Low-Income Postpartum Women: A Randomized Clinical Trial. JAMA. 2017; 312(23): 2381-91.
  2. Lilford RJ, Bentham L, Girling A, et al. Birmingham and Lambeth Liver Evaluation Testing Strategies (BALLETS): a prospective cohort study. Health Technol Assess. 2013; 17(28): 1-307.

One thought on “A Cluster RCT of an Internet-Based Programme to Promote Activity and Reduce Postpartum Calorie Intake in Poor Hispanic Women”

  1. The results of this study are interesting given that the “intermediate” variables show no effect (accepting your comment on the imprecision of calorie intake) but the final outcome does. Of course, this may say something about the use of pedometers to measure physical activity and (although I haven’t read the paper) the method used to monitor calorie intake.

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