Response variables
For repeated measures analysis, the primary response variable of
interest was the SI value. The SI is a continuous variable that ranges
from 0.7 to 0.9, with 0.7 meaning the minimum expected range and 0.9
meaning the maximum normal limit.13–16.SI was
assessed immediately upon admission to the labour room in the active
stage of labour (time 0), at the second stage of labour (time 1), and
every 30 minutes until two hours postpartum (30-60-90-120 minutes, time
2 to 5).