Musculoskeletal back pain: This is the most common cause of back pain in pregnant women, often due to the strain on the back muscles and ligaments from the growing uterus and changes in posture.

Ligament sprain: The ligaments in the back can become stretched or torn due to the increased flexibility and strain during pregnancy, leading to back pain.
Sciatica: Pressure on the sciatic nerve from the growing uterus or a herniated disk can cause pain, numbness, and tingling in the lower back and legs.
Sacroiliac joint dysfunction: The sacroiliac joints can become inflamed or irritated during pregnancy, leading to back pain and stiffness.

Pre-eclampsia: Severe back pain can be a symptom of pre-eclampsia, a condition characterized by high blood pressure and damage to organs such as the kidneys and liver.
Placental abruption: Back pain can be a symptom of placental abruption, a condition where the placenta separates from the uterus, which can be life-threatening for both the mother and the fetus.
Uterine rupture: Severe back pain can be a symptom of uterine rupture, a rare but life-threatening condition where the uterus tears, often in women with a previous uterine scar.

Spinal epidural hematoma: A rare condition where a blood clot forms in the spinal canal, which can cause back pain, numbness, and paralysis.
Osteoporotic vertebral fracture: A rare condition where a vertebral fracture occurs due to osteoporosis, which can cause back pain and deformity.
Spinal infection: A rare condition where the spine becomes infected, which can cause back pain, fever, and neurological symptoms.