The placenta is an organ that forms inside the uterus during pregnancy and helps nourish the baby and filter excess waste that is generated during the gestation months. As the pregnancy progresses, the placenta evolves, and in its evolution the placenta can be classified into four degrees of maturity : 0, I, II and III.
During the second and third trimesters of pregnancy, the placenta presents physiological changes that allow this numerical classification by stages or degrees based on the appearance of intraplacental calcifications.
Degrees of maturation of the placenta
From the ultrasound point of view there are several classifications, but the Grannum of 1979 is the best known, and it is classified as:
- Placenta grade 0: it is characterized in that sonographically the basal plate (near the uterus) and the chorionic plate (near the fetus) are homogeneous. Smooth chorionic plaque without areas of calcification.
- Grade I placenta : when it already has small white areas on ultrasound (eco-refrigerants). In the chorionic plate certain fine and wavy calcifications are identified, scattered at random, and the basal plate does not present calcifications.
- Grade II Placenta : consists of placentas whose basal plate is fully identified and gives the impression that it is separated from the myometrium (muscular layer of the wall of the uterus). In the chorionic plate it is visualized with a very wavy profile with diffuse calcifications . The placenta is not homogeneous due to the different echogenicities in its thickness due to the deposit of calcium. The septa that enter the placenta do not converge.
- Placenta grade III : are the placentas with a large deposit of calcium at all levels. Both the basal plate and the chorionic plate appear highly eco-refrigerant (white color). The partitions of both parts of the placenta already converge and fuse with each other. Inside the placental cotyledons (the tangles that form the chorionic villi) there are areas of calcification and degeneration .
When a placenta presents in grade II or III before week 34, it can be said to be prematurely aged. We have already explained when it is said that there is an old or hypermature placenta.
This could lead to think that the baby developed a restriction in its development due to placental insufficiency, since this insufficiency produces, in the fetus, hypoxemia and nutritional deficiency. The latter is a cause of intrauterine growth retardation, which is why it is important to perform adequate prenatal control, especially in the final stage of pregnancy.
The development of the placenta usually follows a uniform pattern until 20 weeks. Then, its volume increases according to the needs of the fetus. Asymmetric intrauterine growth retardation is usually caused by processes that begin after 24 weeks and lead to placental insufficiency, with premature aging.
Applying the Grannum classification, grade II or III placenta is associated before 34 weeks in 60% of fetuses with growth retardation and grade I or II before 30 weeks in 80%.
The Grannum classification (grades 0-3) is the best known; later other authors, such as the Spanish de la Fuente and Olaizola, made another classification ( grades I-IV ), which is correlated with that of Grannum, with the same placental differentiation criteria.
Ultimately, the degrees of maturation of the placenta constitute the classification that can be used to determine the evolutionary moment in which said organ is located, and ranges from the youngest grade 0 to the most mature grade III.
They are observed by ultrasound and are important for the control of fetal health in the final stage of pregnancy.
In Babies and more | The placenta is a repository of genetic defects that helps the baby to correct or avoid them
