The thickness of 36 mm of the posterior wall of the placenta is not serious and is a normal condition. The placenta is located in the posterior wall is the normal placenta position, usually during pregnancy, the thickness of the placenta is about between 25 mm and 50 mm, the thickness of 36 mm is within the normal range. If the thickness of the placenta is greater than 50 mm, it can be diagnosed as thickening of the placenta, and at the same time, it should be suspected that there is a possibility of placental abruption, if the thickness of the placenta is less than 25 mm, it can be diagnosed as thinning of the placenta, and it should be noted that there is placenta praevia or intrauterine fetal development is restricted. Fetal nutrition mainly depends on the supply of the placenta, it is recommended that pregnant women should have regular obstetric examination, not only to understand the thickness of the placenta, but also to understand the maturity of the placenta, and pay attention to whether the development of the fetus is consistent with the gestational week, if the placenta is too thick or too thin, we should be vigilant about pregnant women whether there are pregnancy syndromes, and if there is any discomfort during pregnancy, we should follow up the consultation in a timely manner.