37 weeks pregnant waist acid is not necessarily early birth, 37 weeks pregnant waist acid has many reasons. In addition to early birth, the common ones tend to be caused by lumbar muscle aches and pains in late pregnancy, hormonal effects, and micronutrient deficiencies.1, early birth: pregnant women who experience early birth can experience persistent lumbar acidity, paroxysmal abdominal pain, and an increase in vaginal secretions, which can be accompanied by blood. Pregnant women who are 37 weeks pregnant also belong to the full-term birth, so do not worry too much; 2, late pregnancy lumbar muscle pain: with the increase in the duration of pregnancy, the upper body of pregnant women will gradually become anti-arch to maintain balance. And at this time increased lumbar curvature, coupled with the abdominal muscles are more flaccid, pregnant women’s lower back muscles will be excessively tight. At the same time, the development of the fetus needs blood supply, it will cause lumbar blood insufficiency, the phenomenon of lumbar acid; 3, hormonal effects: pregnant women in pregnancy will secrete relaxin, as well as increase the weight of the uterus, will make the pelvic ligaments and intervertebral joints, ligaments, relaxation, and then compression to the nerves as well as lumbar vertebrae, the emergence of lumbar acid; 4, the lack of micronutrients: in the late stages of pregnancy, the fetal growth and development of the faster, pregnant women are prone to Lack of various nutrients, especially calcium and vitamins. Once the lack of various trace elements, it is easy to cause lumbago, lumbago; 5, other: pregnant women usually lumbar muscles continue to contract, it will produce lactic acid accumulation in the lumbar or lumbar cold caused by lumbago; when pregnant women appear urinary diseases or pelvic inflammatory disease, adnexitis and other diseases, there will also be the phenomenon of lumbago. So pregnant women in the 37th week of pregnancy back pain, mostly caused by normal physiological factors, if there is also abdominal pain, contractions, vaginal fluid and other conditions, need to be sent to the hospital as soon as possible for related processing.