What is Implantation (human embryo)?

In humans, the initial stage of pregnancy is referred to as implantation.



About Implantation

  • In the early stage of pregnancy, the conceptus clings to the walls of the uterus and the conceptus is called a blastocyst. In order to grow, the fetus receives oxygen and nutrients from the mother.
  • When the eggs leave the ovary, the fertilization process of the eggs begins. This transportation of eggs is done through the Fallopian tubes.
  • When male sperm cells are deposited in the female reproductive tract, they try to unite with the egg and travel to the proximity of the Fallopian tubes.
  • After getting fertilized, the egg has to go through a series of cell division.
  • It takes 7 days for the egg to reach the uterus. By this time the egg with single-cell gets divided and a ball of around 200 cells gets created.


  • Once the egg reaches the uterus, it remains free for about a day in the uterine cavity and then it gets adhered to the endometrium (i.e. The uterine lining).
  • Once the egg gets in contact with the uterine wall, the cells that are on the outer surface of the egg starts growing. Then the egg distorts the uterine lining and actively digs deeper into the tissue.
  • After the 11th day of fertilization, the egg completely inserts itself into the uterine lining.

Implantation Bleeding

  • The implantation bleeding begins when the fertilized egg attaches to the endometrium to commence the prenatal development. Due to this movement of egg, slight bleeding would be observed, which is completely normal.

Symptoms of implantation bleeding

Implantation bleeding is considered to be one of the early signs of pregnancy. This generally begins around a few days before the next menstrual cycle. Women often get confused with period and implantation bleeding.

Here are some of the clearly identifiable symptoms of implantation bleeding:

  • A brown or pink vaginal discharge or spotting
  • Light cramp
  • Headaches
  • Mood swings
  • Tender breasts

Signs of successful implantation bleeding

  • About twenty to thirty percent of women have implantation bleeding. Many women misunderstand the implantation bleeding with the beginning of their period.
  • Body temperature might drop for one day.
  • The most common sign to know that the implantation bleeding has been successful is nausea.

What happens during implantation?

Once the egg is fertilized by a useful sperm, it travels towards the uterus through the Fallopian tube. Then it makes contact with the uterine wall for prenatal development. It usually takes 9-10 days for the whole fertilization process. In case the fertilization process is unsuccessful the eggs get flush out in the next menstrual flow.

To learn more in detail about Fertilization and Implantation, visit BYJU’S.


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