What is the process of implantation in early pregnancy?

The process of implantation in early pregnancy specifically refers to the attachment of the fertilized egg, or blastocyst, to the lining of the uterus, known as the endometrium. This critical step occurs approximately 6 to 10 days after fertilization. During this time, the blastocyst undergoes a transformation and begins to secrete enzymes that allow it to penetrate into the endometrial tissue, firmly anchoring itself and establishing a connection with the maternal blood supply. Successful implantation is essential for the continuation of pregnancy, as it enables the developing embryo to receive nutrients and oxygen from the mother.

Fertilization of the egg occurs before implantation and involves the union of sperm and egg, while the development of the placenta and the release of the egg from the ovary pertain to other stages in reproduction. The first is a consequence of successful implantation and the latter describes an event in the menstrual cycle, neither of which defines the implantation process itself.