Final answer:
During the transition phase of labor, a perinatal nurse would expect contraction intensity readings to be in the range of 50 to 70 mm Hg.
Step-by-step explanation:
The perinatal nurse assessing a laboring woman's contraction intensity by internal monitoring during the transition phase of labor would expect a reading in the range of 50 to 70 mm Hg. This phase is typically the most intense part of labor, with contractions being the strongest and closest together as the cervix completes its dilation to 10 centimeters, allowing for the birth of the baby. The intensity of these contractions is necessary for the final effacement and dilation of the cervix.