Final answer:
Pregnant women often suffer from back strain late in their pregnancy due to the expansion of the uterus, weight of the fetus, and relaxation of ligaments and joints in the pelvic area.
Step-by-step explanation:
One of the reasons why pregnant women often suffer from back strain late in their pregnancy is due to the expansion of the uterus and the weight of the growing fetus. As the uterus expands, it puts pressure on the lower back and pelvic area, leading to back pain. Additionally, the ligaments and joints in the pelvic area become more relaxed and flexible in preparation for childbirth, which can also contribute to back strain.