The placenta - what is it?

The placenta is a temporary organ that nourishes your fetus during pregnancy. The development of this organ starts a few days after fertilization.

Placenta is known in medical language as placenta. It is a unique organ due to the fact that it contains genetic material from two individuals - the fetus and the pregnant woman. The overall task of the placenta is to *exchange circulation between the fetus and the pregnant woman. This means that the placenta ensures that the fetus can exchange oxygen and carbon dioxide (as we breathe through our lungs), but also nutrients, hormones and electrolytes, and remove waste products. The placenta is also known as the tree of life and is made up of a tree-like structure.

How is the placenta formed?

Early in pregnancy, the embryo embeds itself in the uterine wall and divides. One part will form the fetus while the other part starts to form the placenta. The placenta will sit where the embryo chooses to embed itself. This can be high in the uterus (fundus), in the front or back wall, or in the lower part of the uterus. As the pregnancy progresses and the uterus grows, the placenta tends to move upwards. Therefore, if you have a placenta that is low at your routine ultrasound (around 5%), it does not mean that it will be in the same position closer to delivery (around 0.5%).

The placenta contains small pools of the pregnant woman's blood that wash over the blood vessels leading to the fetus. In between, there are filters that ensure that the fetus and the pregnant woman's blood never mix. This protects the fetus from many bacteria but also some viruses. At the end of pregnancy, this filter allows larger molecules such as antibodies to pass through to help build the fetus' immune system. However, blood may be mixed in cases such as trauma, fetal inversion, and invasive prenatal diagnosis, and may be important if the pregnant woman has a negative blood group and the fetus has a positive blood group. (you can read more about it in the article on RhD immunization).

Read about the womb and amniotic fluid here!