Embryology, Fertilization

Fertilization is a complex multi-step process that is complete in 24 hours. The sperm from a male meets an ovum from a female and forms a zygote; this is the point in which pregnancy begins and leads to a 280-day journey for a female. There are two ways to track this process, and they differ by the day counting begins. There are the post-ovulation age and the gestational age, calculated by adding two weeks to the last menstrual period. There are many steps that both the egg and sperm must go through for this process to be successful. Furthermore, the fertilized egg itself goes through drastic changes. This article will detail the process in the following sections.