The most common reason for premenstrual back pain is incorrect position of the uterus, such as retroflexion or prolapse of the uterus, which can cause back pain. Secondly, after the birth of the baby is more strenuous, did not do a good job of menstruation is also one of the reasons for premenstrual back pain, because after pregnancy with the continuous development of the fetus, need lumbar strength to support, the sacral ligament will become relaxed, after the birth if not fully recovered will cause back pain. Third, lumbar diseases, such as lumbar strain, herniated disc and osteophytes can cause lumbar pain.