The intelligent membrane indicates Allah's Greatness:

Dear believing brothers, the placenta is a large disk that accompanies the embryo in the mother's womb and that is cast away upon birth. It is made up of a couple of blood circulations separated by a thin membrane called the placental membrane. The two blood circulations are the blood circulation of the mother and that of the embryo. 

It is well-known that in some cases, the mother's blood belongs to a blood group that differs from that of the embryo's, and that both are separated in the placenta by a thin membrane, which is a miracle of its own, as it separates the mother's blood from that of the embryo but allows food, which is selected most carefully, to pass from the blood of the mother to that of the embryo. It is indeed an intelligent membrane! 

The embryo needs potassium, calcium and other elements; and the membrane allows the passage of all that the embryo needs in order to survive and grow. It also allows oxygen, which the mother gets from the air, to pass from the mother's blood to that of the embryo. Moreover, this membrane allows substances of immunity from diseases and epidemics, since elements of immunity and antibodies are allowed to pass from the mother's blood to that of the embryo. At the same time, this membrane allows poisonous substances and the gases resulting from burning, such as CO2, which is produced in the embryo's body by operations of construction and destruction, to pass from the blood of the embryo to that of the mother. Also, secretions and excrements of the embryo are allowed to pass through this membrane from the embryo's blood to that of the mother.

In short, this membrane allows the passage of the selected food, oxygen, elements of immunity, and excrements resulting from metabolism and burning in the cells of the embryo's body. At the same time, it prevents the passage of germs, bacteria, diseases, or epidemics to the embryo. 

Dear believing brothers, all of this is done without allowing the mother's blood to mix with that of the embryo, as both bloods remain separated from each other by this membrane, which is a Divine Miracle that bespeaks Allah's Infinite Divine Power and Might. 

It separates between the mother's blood and that of the embryo. However, the embryo takes the oxygen, the elements of immunity and carefully selected nutritional elements, and gets rid of excrements through this miraculous membrane, which does not allow germs or bacteria to pass to the embryo. Furthermore, if the mother has an infection, such infection will most probably not be transferred to the embryo through this miraculous membrane. 

It is indeed an intelligent membrane, as described by medical scientists. Let me repeat its functions: It allows the passage of all the things that the embryo needs to survive and grow properly, and it allows getting rid of all the things that are harmful to the embryo. On the other hand, it does not allow entrance of anything that may be harmful to the embryo. All the things that are harmful to the embryo are sent from the blood of the embryo to that of the mother, but they are by no means allowed to pass from the mother's blood to that of the embryo. It is indeed one of Allah's Signs that manifests His Infinite Divine Might and Power!

Dear believing brothers, medical scientists summed up the work of the placenta in that it provides the embryo with oxygen and takes away CO2, i.e. it does the job of the lungs. In other words, the placenta is the embryo's lung. The placenta also provides the embryo with the proper amounts of the digested food necessary for its survival and growth. In this context, it has been found out that the placenta provides the embryo with a daily-regulated food that is proportional to its growth. Therefore, the placenta does the work of the digestive system. It also sends hormones that fix the embryo to the mother's womb and makes the mother's breasts ready to produce milk for the baby.

To wrap up, the jobs and functions the placenta, which most people burry under the ground according to the Suunah, does are miraculous enough to make one fall prostrate to Allah the Almighty.