31 weeks pregnant fetal movement becomes less may be a normal phenomenon, such as fetal rest, pregnant women busy, etc., may also be abnormal phenomena, such as intrauterine hypoxia and other causes. 1. Fetal rest: 31 weeks pregnant fetus will gradually develop a regular routine, fetal movement is more regular, the fetus in the uterus is not always active, the fetus in the uterus rest when the number of fetal movement will become less, this is a physiological phenomenon. 2. Pregnant women busy: 31 weeks pregnant women will be distracted by the busy state, may feel less fetal movement, pregnant women sit down to relax, the number of fetal movements will increase significantly. 3. Intrauterine hypoxia: 31 weeks pregnant fetal movement becomes less, if less than 10 times in 12 hours, consider the fetus intrauterine hypoxia caused by. May be the umbilical cord around the neck, pregnancy with chronic nephritis, pregnancy hypertension and other diseases, affecting the normal blood supply function of the placenta, the effective gas exchange area is reduced, the ability of the fetus to transport oxygen and the use of oxygen decreases, which will lead to a significant reduction in fetal movement. There are many other reasons why fetal movement becomes less in pregnancy 31, when you feel abnormal, you should seek medical examination and treatment in time to avoid adverse consequences.