Which of the following is NOT a sign of labor?

Sudden weight gain is not a sign of labor, making it the correct choice in this context. During labor, women typically experience various physiological signs that indicate their body is preparing for the birthing process. Regular contractions are characterized by their increasing frequency and intensity, which help in the dilation of the cervix. A blood show, which involves the passage of blood-tinged mucus, often occurs as the cervix starts to change and is a common indicator that labor is approaching.

Additionally, back pain can be associated with labor, particularly during contractions or as the baby engages in the pelvis. Weight fluctuations during pregnancy can happen for many reasons, but an unexpected or sudden weight gain does not directly indicate the onset of labor. Recognizing these signs is crucial for nursing practice in maternal newborn care, as they help determine when to assist patients in labor.