Final answer:
Intermittent contractions means they are irregular, which contrasts with the regular contractions of true labor that become more frequent and powerful over time. The correct option is B.
Step-by-step explanation:
At first, the woman's contractions were only intermittent, so the nurse had trouble determining how far her labor had progressed. In this context, intermittent means that the contractions were irregular. They were not occurring in a consistent pattern, which can make it difficult to determine the progress of labor.
True labor is characterized by regular contractions that become more frequent and powerful with time. These contractions lead to the dilation and effacement of the cervix, ultimately progressing to childbirth. The word intermittent describes contractions that do not follow this pattern of increasing regularity and intensity.