Placenta thickness standard and placenta function

Pregnancy is one of the great joys of life. Nowadays, working mothers have a very hard time as they have to work and shoulder the heavy responsibility of childbirth. What pregnant women are most worried about is the development of the fetus in the womb. The placenta is an important tissue that supplies nutrition to the fetus. The standard of placental thickness is generally scientifically defined. Pregnant women can check the thickness of the placenta through B-ultrasound and other examinations. If there is any abnormality in the placenta, it must be taken seriously to prevent accidents. Below is an introduction to the placenta thickness standards and placenta functions.

Placenta thickness

The normal [full-term] placental thickness measured by B-ultrasound is 3.6-3.8 cm, usually not exceeding 5 cm. Under abnormal circumstances, the placenta may be enlarged. Conditions such as blood type incompatibility and diabetes can cause the placenta to be thicker than 5cm. Placental thickening generally indicates complications of the pregnant woman or abnormalities in the growth of the fetus in the uterus. (The normal thickness of the placenta during pregnancy should be between 25 and 50 mm) The membranous placenta is characterized by a large and thin placenta, which is prone to bleeding in the second trimester of pregnancy. If the placenta is small, it can lead to intrauterine growth retardation of the fetus and low birth weight at full term.

Placenta function

The placenta is a transitional organ that grows from the embryo's embryonic membrane and the mother's endometrium during pregnancy in metatherian and eutherian mammals and is used to exchange substances between mother and child. The fetus develops in the uterus and relies on the placenta to obtain nutrition from the mother, while both parties maintain a considerable degree of independence. The placenta also produces a variety of hormones to maintain pregnancy and is an important endocrine organ.

Some reptiles and fish also reproduce by giving birth to their offspring live. The embryo grows some auxiliary structures such as yolk sac and gill filaments that are closely integrated with the maternal tissues to achieve the exchange of substances between mother and child. This structure is called a pseudoplacenta.

There are two independent circulatory systems in the placenta, one for the fetus and the other for the mother (even if it develops to the sinusoidal endothelial type, such as in the late rabbit embryo, there is still a layer of endothelial cells separating the two sides). The chorion can be regarded as a semipermeable membrane, and the area in which all the villi are in contact with the maternal blood is 7 to 14 square meters; when the maternal blood flows in the gaps between the villi and the fetal blood flows in the villi, substances can be exchanged.

Ultrasound grading of the placenta

Placental ultrasound grading is one of the important indicators for evaluating placental function. The placenta is divided into four grades, namely 0, I, II, and III, according to the echo and morphology of the chorionic plate, placental parenchyma and basal plate at different stages of pregnancy. This is a method that relies on the different grayscales of ultrasound images to make judgments with the naked eye. It is somewhat subjective and there are certain differences between different operators.

Pregnant women must do perinatal care during pregnancy and always pay attention to the condition of the fetus in the abdomen. The quality of the placenta affects the healthy development of the fetus. It is best for pregnant women to go to the hospital regularly during pregnancy to learn relevant pregnancy knowledge and observe themselves for any abnormalities. To understand the condition of the placenta, some ultrasound examinations are needed. The thickness and position of the placenta are closely related to the fetus. As long as the pregnant woman pays attention to a reasonable schedule and nutritional combination, the fetus can grow and develop healthily and safely.