Patient's question:
NoDoctor's answer:
The fertilized egg divides into two cells 36 hours after fertilization and into 16 cells 72 hours after fertilization, called a morula. On the fourth day after fertilization, the cell cluster enters the uterine cavity and continues to develop within it. At this stage, the cells have divided into 48 cells, forming a blastocyst ready for implantation. The blastocyst can secrete a hormone that helps it embed itself into the endometrium. Between the 6th and 7th days after fertilization, the blastocyst begins to implant. Implantation typically occurs in the upper third of the uterus. Once implantation is complete, the embryo is securely settled and begins to form the placenta.