The possible causes of right side pain in pregnant women are physiological factors, or pathological factors such as lumbar intervertebral disc herniation and kidney stones. 1. Physiological factors: after pregnancy, due to the growth of the fetus can lead to uterine compression, when the pregnant woman is in the right side of the posture for a long time, it can cause pregnant women right back side pain. 2.Pathologic factors. (1) Lumbar intervertebral disc herniation: when pregnant women combined with lumbar intervertebral disc herniation, due to the fetus leads to increase the load of the mother, lumbar intervertebral discs protruded to the right side, which can lead to pregnant women’s right lumbar flank pain. (2) Kidney stones: when pregnant women combined with the right side of the kidney stones, the stone blockage can not be discharged, resulting in pregnant women with right flank pain. To sum up, when pregnant women have right flank pain, they should go to the hospital in time for further examination, to clarify the cause of the disease, and under the guidance of professional doctors for treatment.