The simple definition of conception is the process of becoming pregnant involving fertilization or implantation or both. [Merriam-Webster Dictionary]
Conception vs. Implantation
Conception means different things to different people and is a highly debated topic. The personhood debate that is the status of being a person has revolved around conception occurring either when the sperm and the egg join or when the sperm and the egg attach to the uterine wall. In 1965, the second definition became the legal definition, and according to the American Congress of Obstetricians Gynecologists, conception means implantation.
Conception and Ovulation
Most of the time, a woman won’t know the exact date she conceives. It can be even more confusing considering that if you do conceive, your pregnancy will begin two weeks before conception even occurs. Conception occurs two weeks after a woman’s last period after ovulation is complete. During ovulation, an egg is released. In order for conception and implantation, the egg must be fertilized by a single sperm. When this happens, the sperm penetrates the egg and within 24 hours forms a new cell called a zygote.
Although millions of sperm are released when a man ejaculates, only a few survive the journey to the egg. After the winning sperm penetrates the egg, a barrier forms immediately around the egg. Furthermore, anywhere between a third to a half of fertilized eggs will never even implant. Implantation can take from 5 to 18 days, but is an average of 14 days. During this stage, the zygote attaches to the uterine lining. Once this process is complete, conception is considered complete, and the pregnancy has realistically begun. [!][@]
Best time for Conception
This process is extremely time sensitive. The later the implantation, the less successful the chances for pregnancy. If the egg is not fertilized, the egg will dissolve. Next, hormonal fluctuations will otherwise begin menstruation. Eggs can live at most for a day. Sperm can live up to 2 days. Therefore, the conception/implantation process can occur if a woman has intercourse the day before ovulation as well. The best time for conception to occur is the day before ovulation, because the sperm requires a 12-hour waiting period in the uterus before they can fertilize the egg.
[@] The Guttmacher Report on Public Policy
The Implications of Defining When a Woman Is Pregnant
2005; Volume: 8; No: 2
[!] Human Fertilisation and Embryology Authority
American Pregnancy Association