After giving birth to a child every night to sleep in the middle of the night back pain, may be physiological factors, such as uterine contraction, lumbar burden is too large; may be caused by pathological factors, such as lumbar intervertebral disc herniation and pelvic inflammatory disease and so on. 1. Physiological factors: after giving birth to a woman, uterine contraction will induce radiating pain, which will cause postpartum lumbar pain; women tend to be less active during the menstruation period, and if they often lie down in bed to rest, it will result in a lack of lumbar muscle exercise, which will easily lead to excessive burden on the lumbar region and induce pain symptoms when sleeping. 2. Pathological factors: such as lumbar muscle strain and lumbar dorsal fascia strain, as well as pelvic inflammatory disease and lumbar intervertebral disc herniation, these diseases may cause middle-of-the-night back pain. It is suggested that women need to exclude physiological factors, and then need to go to the regular hospital to receive examination, according to the cause of the treatment under the guidance of specialists.