Final answer:
Pregnant women often suffer from back strain late in their pregnancy due to rapid expansion of the uterus, increased curvature of the spine, and hormonal changes.
Step-by-step explanation:
One of the reasons why pregnant women often suffer from back strain late in their pregnancy is the rapid expansion of the uterus. During the third trimester, the uterus grows larger and takes up more space in the abdomen. This extra weight and pressure on the lower back can cause pain and discomfort.
Another factor that contributes to low back pain during pregnancy is the increased curvature of the spine. Pregnant women often move their shoulders back to maintain balance, which increases the curvature of the spine and puts more stress on the lower vertebrae.
Lastly, hormonal changes during pregnancy can also play a role in causing back pain. Relaxin, a hormone produced during pregnancy, relaxes the ligaments and joints in the pelvic area, which can lead to instability and contribute to low back pain.