What is the placenta?

The placenta is the main organ of pregnancy and its function is of vital importance, since it is the connection between the mother and the fetus. It originates with fertilization, grows together with the baby and dies after it is born, its primary task being to guarantee the nutrition of the fetus.

If you have done a pregnancy test and confirm that you are in the sweet wait, you need to know about the formation of a very important organ in pregnancy: the placenta. You have probably heard about it many times, but on few occasions do they explain to you how it really works or how its formation occurs; including possible problems that could affect its proper functioning. 

For this reason, we took on the task of investigating a little more about the placenta, to clarify all those possible doubts that may arise around this embryonic organ. 

When does the placenta form?

Once the egg is fertilized by the sperm, it begins its journey to the uterus and a week after fertilization has occurred, the embryonic implantation occurs in the uterine wall, being at this moment when the formation of the placenta begins, normally located on the anterior or posterior face of the uterus so as not to obstruct the birth canal. But it is in the eighth week of pregnancy when the placenta begins to function, since the fetus begins to feed through said organ.

Thus, its development occurs from the cells of the egg and sperm that formed the fetus, becoming a fundamental organ for the growth and nutrition of the baby, creating a direct connection with the mother. 

In its composition, we can distinguish, as parts of the placenta, the following:

A maternal compound or decidua basalis, which is the uterine mucosa or endometrial membrane that transforms to house the fetus.

A fetal component known as a trophoblast. The trophoblast is a composition of many blood vessels that cross each other, generating a chorionic cavity with different placental compounds.

In addition, there are different types of placenta depending on their location in the uterus, which we mention below:

When the placenta adheres to the anterior area of ​​the uterus, that is, in a frontal location towards the womb, it is called an anterior placenta. Although, if it is very high, it is known as a high anterior placenta. If it attaches behind the uterus to the maternal pelvic bones, it is called a posterior placenta. Both positions are considered normal for the development of the fetus and for the mother.

Now, if the placenta is placed in the lower area, partially covering the uterine cervix, it is known as a non-occlusive placenta. But if it completely covers the cervix, it is called occlusive placenta or better known as placenta previa, which deserves extreme monitoring and care for a happy pregnancy term.

And how much does the placenta weigh?

The placenta at the end of pregnancy has a weight that ranges between 450 and 550, with an approximate thickness between 1.5 and 3 centimeters, while its diameter is between 15 and 20 centimeters.

What is the placenta for?

As the baby grows inside the womb, the placenta develops along with it, adapting to the needs of the fetus in its nest. Among the main functions of the placenta we can highlight that, through it, all the nutrients that the baby needs to grow and develop properly are transmitted from the mother, this being its main mission. Thus, the baby can absorb from the mother the minerals, vitamins, fatty acids, amino acids and glucose that her body needs to grow properly. But, in addition to that, the placenta also serves the following:

Functions as a lung for the fetus: If you have ever wondered how a fetus breathes? You should know that the oxygen that the baby needs to breathe is transported by the blood supplied by the mother to the uterus through the placenta, which is why it is a very important organ for carrying out the respiratory function. Keep in mind that the baby is submerged in a bag with amniotic fluid inside the uterus, making it impossible for his lungs to work on their own, so the placenta and the umbilical cord join to serve as a transport for the oxygen that the fetus needs to breathe.

Protective action:The placenta is responsible for protecting the fetus from the maternal immune system, as it prevents the embryo from being detected as material foreign to the mother and from being attacked. In addition, this organ becomes a placental barrier, preventing external bacteria, germs or other toxic agents from affecting the fetus. However, there are certain viruses that can cross this barrier and affect the baby’s immune system, such as the syphilis virus or the toxoplasmosis parasite. On the other hand, the amniotic sac and placenta form a protective layer for the baby against blows, strong impacts or changes in temperature, providing a safe, cozy and pleasant space. In addition, the placental circulation keeps the blood of the mother and the fetus separate. 

As a waste filter for the baby: The placenta functions as a filter for the baby, because through it the waste of the fetus is eliminated by the mother’s bloodstream, mainly carbon dioxide, being subsequently excreted through the maternal renal system. Thus, the placenta is responsible for keeping all harmful substances that could affect the fetus away from its organic system.

It has an endocrine function: the placenta helps in the synthesis of female hormones and estrogens, which the woman needs for the fetal implantation in the uterus, as well as for the growth of the mammary glands and to produce placental lactogen, preparing the body for breastfeeding. For example, through the placenta the hormone called chorionic gonadotropin is manufactured, which is necessary for the continuation of pregnancy. 

In short, the placenta is an interesting organ that, prior to pregnancy, does not exist in the female body and after childbirth does not survive, disappearing completely from the uterus without leaving traces, but its importance is vital for the healthy growth of the fetus.