Final answer:
During pregnancy, constipation can be caused by the growing uterus putting pressure on the bowels and slowing down digestion.
Step-by-step explanation:
During pregnancy, constipation can be caused by the growing uterus putting pressure on the bowels, which slows down digestion. This decreased peristalsis, or the movement of food through the digestive tract, is also responsible for pregnancy-related constipation as pregnancy progresses. Therefore, the nurse should respond to the client by selecting option A: 'The growing uterus is putting pressure on your bowels, slowing down digestion.'