For nested longitudinal data collection (India)
SECONDARY
For estimating the sample size for the nested longitudinal study, the research team considered a secondary outcome indicator, that is, proportion of pregnant women whose blood pressure, weight and Hb are checked at least once in each trimester. As there are no reliable estimates for this indicator from either Tamil Nadu or Assam, we assumed it is approximately 50%. For our study to detect the relative risk within 20% of true value, which we assumed to be 1.25 (