I believe that many expectant mothers will stare at the examination form for a long time after the prenatal check-up. The data is normal and they feel sweeter than honey. There are some values that expectant mothers can use to judge the condition of their fetuses through the normal range. But in the third trimester, a new indicator will be added to the pregnancy test sheet. Mothers will be confused about this indicator. There are only four simple words. Have you ever been in a state of confusion? The four-character indicator refers to the placental grade. This indicator appears in the third trimester of pregnancy. This new indicator will appear on the B-ultrasound report starting from the 28th week of pregnancy. Doctors can learn about the condition of the placenta based on the placental grading to determine the condition of the fetus. Therefore, placental grading is of great significance to the healthy development of the fetus. Role of the Placenta The placenta is the life support system of the fetus. The blood supply is established between 10-12 weeks of pregnancy. Eventually, it invades 80 to 100 uterine blood vessels called spiral arteries and grows capillaries totaling 50 kilometers long. The tiny, finger-like projections formed by placental cells are called placental villi. The villi contain fetal capillaries and absorb oxygen, nutrients and dispose of waste products in contact with the mother\’s blood. Placenta Level As the gestational age increases, the placenta will also change from new to old, which is called placental maturity, and is divided into four levels. How is it graded? In fact, doctors use ultrasound to determine the maturity of the placenta, mainly based on the calcification spots on the placenta. If the calcification points are scattered and distributed, it is diagnosed as grade 2, and if the calcification points are connected into pieces, it is diagnosed as grade 3. Level 0: Second trimester, approximately 12 weeks to 28 weeks of pregnancy. Level 1: 30-32 weeks of pregnancy, marking the early stage of placental maturation. At this time, the placenta can provide good nutrition to the baby. Level 2: The placenta is nearly mature after 36 weeks of pregnancy. However, if the placenta maturity reaches level 2 around 20 weeks of pregnancy, or if the placenta maturity reaches level 3 around 35 weeks of pregnancy, it indicates that the placental function is reduced. Level 3: The placenta enters level 3 at 38 weeks, indicating that the placenta has matured and begun to age, and its ability to transport oxygen and nutrients is reduced. Under normal circumstances, the closer to term, the more mature the placenta is, and the function of the placenta gradually decreases as the fetus matures. In addition to placental grade, experienced doctors will also check the amniotic fluid volume, umbilical artery blood flow velocity, fetal heart rate monitoring, urinalysis and other indicators to comprehensively consider the health of the fetus. Generally speaking, if placental grade 3 is found before 37 weeks, combined with the value of the biparietal diameter and the estimated fetal weight of 2,500 grams, the placenta should be considered to have precocious maturation and be alert to the possibility of intrauterine growth retardation and placental aging. Pregnant mothers need to pay attention to pregnancy diseases such as gestational hypertension, diabetes, kidney disease, or smoking habits (including second-hand smoke) during pregnancy, which will reduce the blood supply to the placenta and accelerate the aging of the placenta.