Importance of Setting Up Reference Intervals and Multiple of Medians (MoM)

I was interested in the article of Kianpour et al. on reference intervals for thyroid hormones during the first trimester of gestation from an area with sufficient iodine level 1. The unavailability of data in this population had triggered this study where 436 pregnant and 444 non-pregnant women were recruited. I appreciate the great effort taken by the authors to recruit such a large population for the study. Following screening as per exclusion criteria 291 pregnant women were eliminated and thus the data of 145 pregnant was included for analysis. However, the article mentions the analysis of samples of 185 patients. The authors have also calculated the multiples of medians (MoM) to unitise different laboratory reports.