As your body changes during pregnancy, your back must work in new ways. This can be painful if your back isn’t prepared. Back pain is due to many causes. Physical changes to your body can strain your back and its supporting muscles. Also, certain hormone levels (chemicals that carry messages throughout the body) increase during pregnancy. This can affect how the muscles and joints work together. All of these changes can lead to pain.
The spine is the column of bones that runs down your back. It has three curves: the cervical, thoracic, and lumbar. These curves support your body and help you keep your balance. Muscles in your back and abdomen (stomach) brace and support the spine. Muscles in your buttocks, pelvis, and thighs work with your spine to let you twist, bend, and lift.
During pregnancy, changes in your body affect your back and posture (how you position your body). Your body’s shape and size change, making your muscles work harder. As the body prepares for childbirth, hormones cause pelvic muscles, ligaments, and joints to loosen. This can lead to pain. These changes may also cause you to use poor posture (positions that strain the spine). Over time, poor posture often results in back pain. Talk with your healthcare provider about whether a maternity support belt might help relieve some of the pressure and pain in your lower back.