Strengths and limitations
LATE PREGNANCY
Strengths: We evaluated EMEP in the home setting in late pregnancy with a sham control to assess the “pure” above placebo effect of EMEP on an important clinical outcome of spontaneous vaginal delivery compared to operative delivery. Our primary outcome was clearly defined and easy to ascertain and we had complete data on this metric. Our sample size was based on pilot data from a smaller earlier trial from our center. Analysis was by intention to treat.Limitations: The effect of EMEP on spontaneous vaginal delivery within our trial was smaller than that from the pilot guidance data, effectively underpowering our trial; post hoc calculation indicated that our sample size of 234 had only 18.7% power to assess spontaneous vaginal delivery rates of 51.3% vs. 44.4% that we found. We used self-reported night sleep duration; actigraphy derived sleep duration was generally preferred over self-reported duration [