Implantation: Early Pregnancy

Implantation

Implantation is substantial process in the early pregnancy typically characterized by the attachment of the embryo to the epithelial lining of the uterus. The embryo undergoes the process of implantation at the blastocyst stage. It is an active process responsible for the blastocyst apposes, adhesion and progressively invasion into the endometrium to establish the placenta.

Normal implantation zone: Implantation normally takes place in the body region of the uterus which is the corpus uteri in a functional layer called the endometrium. The endometrium is an epithelial layer line the uterus. This layer after that will expose to several changes to help establishing the embryo into the uterus.

Implantation Window:

The reception phase of the uterus to the blastocyst occurs after 7-9 days of the ovulation and takes 4 days during the 20th and 23rd of the last menstrual cycle. At this time, the uterine mucosa becomes thick, highly vascularized and contains large amount of glycogen and that allow to have a favorable condition and good nutrition for the blastocyst. During this phase, a series of changes occur in the epithelial cells which line the uterine wall. The long, thin, and regular microvilli of the uterine epithelial cells are converted into irregular flattened projections in purpose of ease the attachment and movement of the fertilized egg. In order to be receptive, the uterine lining exposes to the ovarian steroid hormones estrogen and progesterone in sufficient amounts with proper timing. They help to thicken the lining of the

Zona Hatching is the process by which the expanded blastocyst breaks through and escapes from the zona pellucida which is a glycoprotein layer surround the blastocyst and replace it with the trophoblast, which is going to get rise to the placenta after implantation. This hatching process occurs on day 3 of embryonic development. It is done in order to increase the chances of embryo implantation and