Decoding Placenta

(Combined writing of my extensive reading and podcast of Dr.Raman Subramaniam, Consultant Obstetrician and Gynaecologist).

Image taken from google

Placenta is a huge endocrine organ that produces massive amount of estrogen and progesterone. It is also known as transient organ that plays a vital role in ensuring the health of the fetus during pregnancy and holds the key to understanding pregnancy disorders.

General functions of placenta:

-  Attachment of  fetus to the wall of uterus.

-Supplies all the nutrients, carbohydrates like sugars, amino acids and transfers a lot of stuffs but unfortunately it also transfers drugs, viruses and good things like immunoglobulins which actually protect the fetus and the last one of course the excretory organ as well where it excretes carbon dioxide from the fetus. But, one of the most important nutrient is the oxygen.

How does the oxygen reach the baby through placenta?

Basically, placenta has got the mother side and the fetal side. The mother actually has a trigger in the brain through the progesterone which is produced by the placenta which actually makes the mother’s breath deeper. This will flush oxygen to the lungs and this actually then goes through the mother’s side of the placenta. From the mother side, then it goes to a space which is like a lake between where it diffuses across to fetal side.

When does placenta becomes fully functional?

In the initial part of development, placenta is all round, a whole sac and then gradually parts of it disappear and it sort of becomes discrete structure and from then on it remains like that. It reaches its peak of growth around trimester and that’s when after this it doesn’t grow. And then, it starts slowly functionally becoming less efficient until it finally comes out with the delivery.

What is it made of?

It is made up of cells that are originated from embryo. The developing embryo from fertilization forms ball of cells that then divides into two parts, the inner cell mass forms the fetus and outer cell mass forms the placenta and then it comes down the Fallopian tube after fertilization and enters into uterine wall and attaches itself to the lining of the uterus wall (the one that shed every month as menses) and it then burrows itself to the wall of this cells and then it develops into placenta.

What determines a good placental health?

Amount of cells that form the placenta. Development of the placenta, the number of cells that actually form the placenta particularly in twins where you can find one baby is smaller than the other in which one placenta is smaller than the other. 

Maternal disorders. The diseases associated with the mother like high blood pressure, hypertension, diabetes and certain other diseases affect the placenta. 

Placenta previa

Placenta that is lying in the lower part of uterus, overlying the cervix and there are four grades, type 1,2, 3 and 4. The major placenta previa are the 3 and 4 which cover the cervix and the minor ones are type 1 and 2. Sometimes, when there is a previous cesarean scar and the placenta implants over that area, that area is devoid of the lining of uterus and then the placenta can invade into the wall of the uterus and then it becomes the accreta or it just goes right into the myometrium and becomes the increta and it goes through and through the uterus to the outside wall is called the percreta. This will induce c-section delivery because normal delivery is not possible.

Do twins necessarily have two placentas?

It depends on the type of twining. There are two types of twins that are inclusive of identical twins and non-identical twins. Non-identical twins are two separate eggs which are fertilized separately and they have two different placentas. In identical twins, they have single placenta and may have two sacs or only one sac.

Can cancer cells cross the placenta?

It is well-known for many years that certain types of cancer cells cross the placenta like the skin cancer (melanoma), breast cancer and small cell cancer of the lung but it just 0.01% of probability because the placenta itself is very efficient in preventing the crossing of cancer cells. But some of the cancer cells are very aggressive and they stick in, grow and then burrow into it and then enter from the maternal side into the fetal side.

Cultural differences in treating placenta

Historically, there have been no records of any people consuming placentas but it seems to be a more recent fact that people think that they feel young, it prevents depression, it has got minerals and vitamins therefore it is good for them. It is very controversial. If we look at very small number of studies that we have looked at in which people have eaten the placenta shown that there are no complications and these people are denoted as placentophagy. Others do encapsulation, they freeze it, give it to a company, dehydrate it and make it into pills and eat it. In either way, there is still risk of infection because the vagina is not sterile, it is full of bacteria and even the C-section has the possibilities of having harmful microorganisms. Therefore, currently it is not advised to consume placenta.