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.
For some women, implantation bleeding is very light, similar to one of the last days of your period, or a very light period day, when you just need to wear a panty liner. Your implantation bleeding can last only a couple of hours, and then itâs gone. For other women, they might have spotting on and off for a couple of days. However, there are even others who claim that they had heavier implantation bleeding that lasted up to four days, just like an average length of a period.