The standard of placental thickness after pregnancy is related to the week of pregnancy, and the standard of thickness varies in different weeks of pregnancy. In the whole pregnancy, the change of placenta thickness is generally thickened first and then thinned, i.e., the placenta gradually thickens from absent to present in the early to middle pregnancy, and becomes relatively thinner in the late pregnancy. The thickness of the placenta can be measured by ultrasound, and the thickness of the placenta is too thick or too thin in different weeks of pregnancy. The thickness of the placenta can be measured by ultrasound. If the placenta is too thick, it usually indicates that the pregnant woman has comorbidities, or the placenta is prematurely matured and calcified, placenta abruptio, giant placenta, placenta sinus dilatation, etc., so regular ultrasound examination is needed to monitor the placenta; if the placenta is too thin, we should pay attention to exclude the membranous placenta, which is characterized by large and thin placenta area and easy to bleed in the middle of pregnancy. If the placenta is small, it can lead to fetal growth restriction and low birth weight babies. The thickness of the placenta, although related to the week of gestation, is not a critical factor in determining the health of the fetus. The most important thing is to monitor the intrauterine condition of the fetus and to seek medical attention in case of fetal danger. If you have abdominal pain or bleeding, you should go to the hospital promptly.