Implantation represents attaching of the blastocyst to the shell of the uterus, where it then starts do dig in. Blastocyst usually nests in the upper half of the uterus on the front or rear shell. Shell of the blastocyst is made by one layer of cells in all but one area where three to four layers of cells are found. Inner cells on that thickened spot on the blastocyst start do develop into an embryo, and the outer cells dig into the uterus shell, forming placenta. Placenta has an important role of creating hormones that aid your body in understanding and following through with your pregnancy, enabling oxygen and nutrients exchange in between mother and the new living being. Implantation begins in between 5 to 8 days after fertilization and is done by the 9th or 10th day.
Obvious implantation symptoms
Typical implantation symptoms vary and there is a lot of confusion regarding false alarm pregnancies. Even though most women experience signs of implantation in the couple of weeks after fertilization, they are commonly very subdued and not obvious. Some of these symptoms may occur because of other reasons, which have no straight correlation to the pregnancy itself.
- Late periods
- Implantation bleeding
During implantation, 5 to 6 days after merging of the egg cell and a spermatozoid, the so called implantation bleeding can occur. This is a minor bleeding, commonly accompanied by cramps in the lower part of the stomach, which is caused by contraction of the uterus muscles as the blastocyst is finding its way into it.
- Nausea and inability to withstand smells
These symptom can also indicate pregnancy, being caused by physical and hormonal changes that occur in a woman’s body during pregnancy. Some women experience no nausea to speak of, while other women experience severe nausea, mostly in the mornings.
- Swollen and sensitive breasts
This symptom is fairly common with women who experience it slightly before their periods. In case there is no period to be noted, there is a high chance that pregnancy is in effect.
Increased volume of blood in the body causes strain and tension inside the head, which does show with varying headaches. Some women experience this symptom during the entire pregnancy.
- Back pain
Due to the growth of the uterus and the pressure it causes to the nerve endings in its proximity, this is a common symptom of early pregnancy experienced by a vast percentage of women.
Blastocyst plays a critical role
Shell of the blastocyst creates an outer shell which then surrounds the embryo. Inner layer of this shell is developed in about 10th to 12th day, creating the so called amniotic cavity. This cavity starts to fill up with clear fluid (known as amniotic fluid) and starts to spread inside the uterus mucus, branching across like a tree. This shape allows the surface area to increase significantly, improving the exchange rate of oxygen and nutrients in between mother and the child. Placenta is completely formed with about 18 to 20 weeks into pregnancy, but it does proceed to grow during the entire pregnancy process, weighing in at about 500 grams in the end.