A nurse is caring for a client who is a primigravida, at term, and having contractions but is stating that she is "not really sure if she is in labor or not." Which of the following should the nurse recognize as a sign of true labor?

A. Station of the presenting part: Station refers to the position of the fetal presenting part in relation to the maternal ischial spines. While it can indicate fetal descent, it does not confirm the presence of active labor and may not change significantly early in the process. B. Pattern of contractions: Contractions in true labor are typically regular and increase in intensity, but alone, they do not confirm true labor. False labor can also involve contractions that mimic this pattern, making them less reliable as the sole indicator. C. Rupture of the membranes: Rupture of membranes can occur before true labor begins or even without labor. While it often precedes delivery, it is not definitive evidence that labor is active, especially if no cervical change is observed. D. Changes in the cervix: Effacement and dilation of the cervix are the hallmark signs of true labor. These changes confirm that uterine contractions are causing physiological progress toward delivery, distinguishing true labor from false labor.