The 31st week of pregnancy belongs to the late stage of pregnancy, at this time the fetus has the characteristics of slower growth and development than before, rich expression, lungs and digestive system development gradually mature and so on. The growth and development of the fetus in the 31st week of pregnancy is slower than before, the wrinkles of the fetus are reduced, the subcutaneous fat is gradually enriched, and the skeletal muscles are developing, at this time, the weight of the fetus is about 1,600 to 1,800 grams, and the diameter of the diameters of both parietals can reach about 7.7 centimeters. The expression of the fetus in the 31st week of pregnancy is getting richer and richer, and you can see the fetus touching its face and eyes, yawning, sucking fingers and other actions. The fetal lungs and digestive system are basically fully developed, with the ability to breathe and secrete digestive juices, and the amniotic fluid that the fetus drinks in is able to be excreted into the amniotic fluid through the bladder. If there are abnormalities and other abnormal manifestations of the fetus in the 31st week of pregnancy, it is recommended to consult a doctor in time to clarify the cause of the disease and treat the symptoms after perfecting the relevant examinations under the guidance of the doctor.