Fertilization: Sperm Penetrates Egg. It takes about 24 hours for a sperm cell to fertilize an egg. When the sperm penetrates the egg, the surface of the egg changes so that no other sperm can enter. At the moment of fertilization, the baby's genetic makeup is complete, including whether it's a boy or girl.
Implantation bleeding is an early sign of pregnancy and only experienced by 1/3 of women. Discover when and what to look for as a sign of implantation. Implantation bleeding is an early sign of pregnancy and only experienced by 1/3 of women.
What is Implantation Bleeding? Implantation bleeding is a common process, during which the embryo attaches to the lining inside the womanâs uterus. Often, this bleeding happens between the 6th and 12th days after the embryo has formed, or somewhere between the 2nd and 7th days before period.