A fertilized female human egg typically attaches to the lining of a woman’s uterus within ten to 14 days of conception.
More Info: There is often what’s called “implantation bleeding” as a sign of this earliest phase of pregnancy. The bleeding is light and does not last long, usually one to two days. It also does not affect all women and is commonly mistaken by first-time mothers-to-be as early menstrual period bleeding. Only a very few women experience implantation bleeding that is heavier than a normal period.
A critical element for human eggs are so-called granulosa cells or handmaidens. They envelop a woman’s eggs and feed them with hormones and nutrients so that they can develop properly and become optimized for the conception and implantation stages. Researchers recently found that two proteins, c-Jun and TAF4b, are critical to the proper development of these handmaiden layers. The two substances combine to provide the genetic code underpinning for healthy granulosa cells.
A full understanding of the functioning of healthy granulosa layers is expected to impact positively both the fields of in-vitro fertilization and ovarian cancer treatment. Without the TAF4b protein for example, laboratory mice became infertile. But the big surprise for researchers was the second c-Jun protein. Until recently, scientists had not realized that his protein, also found in certain cancers, was also present at the most fundamental of female life-giving stages.
How Is Pregnancy Defined?
What’s amazing about the idea of conception and implantation is that in the United States, the official definition of pregnancy varies widely. Some states define pregnancy beginning at fertilization, while others pinpoint the start at conception. In 1998, the U.S. Congress narrowly rebuffed a law that would have federally mandated the definition that pregnancy begins at that earlier conception stage. It is a battle the pro-life activists are not ready to soon give up, and recently, with the development of more sophisticated contraceptives, it is expected to be lobbied for as a law once more.
Mayo Clinic – “Implantation Bleeding”, Retrieved November 21, 2010 from http://www.mayoclinic.com/health/implantation-bleeding/AN02029
“Healthy Eggs Helped By A Surprising Pair Of Proteins.” Medical News Today: Health News. N.p., n.d. Web. 22 Nov. 2010. http://www.medicalnewstoday.com/articles/37859.php
The Guttmacher Report on Public Policy- “The Implications of Defining When a Woman is Pregnant”, May 2005, Retrieved November 21, 2010 from http://www.guttmacher.org/pubs/tgr/08/2/gr080207.html