Tummy hardness and tightness caused by 31 weeks of pregnancy can be divided into two parts, physiological and pathological. Physiological factors are usually caused by irregular contractions of the uterus, which can be adjusted through rest and diet; pathological factors may be caused by preterm labor, vaginitis, excessive amniotic fluid, etc., and require appropriate treatment measures according to the cause. The physiological factor is that the fetus is moving a lot during this period, which stimulates the uterine wall and causes the contraction of the uterus to become hard and tight. It is recommended to take more rest, relax, avoid overwork, stay up less, eat more light and easily digestible food, and eat less spicy and stimulating food to avoid stimulating the uterus contraction. Usually persistent hard and tight stomach, need to go to the hospital for examination. Secondly, pathological factors suggest a timely visit to the hospital for a 3D ultrasound to check whether the fetal development is compatible with 31 weeks. In addition, it is necessary to measure the depth of amniotic fluid, amniotic fluid index, pay attention to the position, thickness and maturity of the placenta, and also pay attention to whether the umbilical cord is around the neck. 1. Premature labor: the length of the cervix needs to be measured under ultrasound. The cervical length <2.5cm indicates the possibility of preterm labor, it is recommended to be hospitalized for fetal preservation treatment, and magnesium sulfate is needed to suppress contractions; the cervical length >2.5cm can be preserved at home by itself, and patients can take some oral Chinese medicine under the guidance of professional physicians, such as fetal preservation spirit or fetal preservation without worry tablets. Pregnant women are advised to lie on their left side and rest properly. Sexual intercourse should be prohibited because it may stimulate contractions and cause preterm labor; 2. Vaginitis: vaginal inflammation can produce stimulation and cause contractions. It is recommended to do examination of vaginal secretions, laboratory tests for mycoplasma and chlamydia, and pay attention to whether there is bacterial infection. The presence of vaginitis should be treated with medication in time. The commonly used drug is nifurtimox. After treatment, the inflammation will gradually improve and the contractions will be weakened. When taking oral drugs to inhibit contractions, pay attention to monitoring whether the contractions are relieved; 3, too much amniotic fluid: some pregnant women have too much amniotic fluid and high uterine tension, resulting in a hard and tight stomach. In this case, you need to do a fetal heart monitoring check, pay attention to the fetal heart condition, and at the same time strictly control your diet to avoid excessive amniotic fluid.