At least 50% of pregnant women will experience back pain (1-4), with many suffering from severe discomfort that impacts their activities of daily living. Pregnancy-related back pain can be multi-factorial and rarely only has one cause. Back pain, wrist pain and leg cramps are the most common complaints reported.
The average healthy weight gain is approximately 30 lbs, most of which is around the abdomen adding a significant frontal load. The added weight puts stress on the back, hips, knees and feet/ankles. Additional weight can lead to altered posture and biomechanics as we change the way we sleep, stand, and move during pregnancy. As the baby grows and the uterus expands, the abdominal muscles also stretch and lose their ability to support as they did. The change in posture, shifting forward, may cause pain and discomfort specifically in the lower back.
During the third trimester, levels of the hormone “relaxin” increase and contribute to the loosening of joints in order for the pelvis to accommodate for enlarged uterus, the baby and later birth. However, the loosening of joints can decrease joint stability and further alter posture. Other structures including musculature may be taxed, resulting in a predisposition to pain and injury. This may result in back pain.