Is Zhang the new Friedman: How should we evaluate the first stage of labor?

Norms used to describe and evaluate the first stage of labor have been historically based upon data from the middle of the twentieth century. More recent data has characterized the normal first stage of labor differently including that the latent phase of labor is longer not transitioning from latent to active labor until about 6 cm of cervical dilation in a majority of women, regardless of parity or whether labor was spontaneous or induced. Additionally, the amount of time that can take for progress to be made in active labor be longer than previously understood. These two factors would lead to a change in management with the diagnosis of arrest of the first stage of labor being made at 6 cm cervical dilation or beyond in the setting of ruptured membranes and no cervical change for at least 4 h of adequate contractions or 6 h of inadequate contractions.