38 hours after egg and sperm meet, the fertilized egg quickly begins dividing. By 46 hours, the two cells have become four; by 62 hours, the four cells have become eight.

By day four, the embryo has an amazing 64 to 160 cells, and is called a morula. At this point, the embryo leaves the fallopian tube for the uterus. Up until now, the embryo has been covered by a tough, transparent membrane. The zona pellucida is like a chicken egg’s shell! Underneath the zona pellucida, the multiplying cells condense into one embryo, called a blastocyst.

On day six or seven after fertilization, the blastocyst finds a thin spot in the hard zona pellucida and “hatches” from the shell! This delicate, unprotected blastocyst then braves the scary journey from its safe shell to the uterine wall. The moment the embryo implants itself in the endometrium, you have officially become pregnant. Yeay!!