Hidden pain on the right side of the waist in pregnancy may be related to the following reasons: 1, there may be muscle spasms on the right side of the waist. This situation is often seen in the rapid growth of the fetus, for example, in the third to sixth month of pregnancy, due to the rapid growth of the fetus as well as the increase in amniotic fluid, resulting in the load of the abdomen is relatively large, which will make the lumbar muscles are in a relatively tense state for a long time. If the patient takes a certain protective posture, such as often to the right side of the side lying or to the right side of the inclined sitting position, will make the right side of the lumbar muscle spasm, and then cause hidden pain. 2, there may be fasciitis. This is often due to the patient during pregnancy, the right side of the waist is not good warm, this part if cold, easy to cause deep fascia to produce aseptic inflammation, then cause local pain. 3, there may be lumbar disc herniation aggravation of the situation. There are many women in pregnancy, there will be lumbar disc herniation symptoms aggravate the situation, this is mainly due to the rapid growth of the fetus, the lumbar spine load aggravation caused by. This is mainly due to the rapid growth of the fetus, which increases the load on the lumbar spine. When the fetus grows rapidly, the load on the lumbar spine increases, which in turn increases the pressure on the intervertebral discs, which may lead to an increase in the pressure of the intervertebral discs on the nerve roots, and then the pain in one side of the lower back occurs.