It can take anywhere from 7 to 14 days after ovulation and conception for implantation bleeding to occur.
More Info: When an egg is released during ovulation, it must be fertilized within 24 hours. After the egg has been fertilized, it then needs to travel down the fallopian tube and to the uterus to become implanted.
As the egg travels it also grows in size. During that time, a tissue called trophoblast develops around the egg. The trophobast is what actually attaches the egg to the uterus by eating away at the lining of the uterus and embedding itself within the lining. When this happens, the blood vessels from the mother actually start to feed the fertilized egg, by diverting the blood supply. This blood can leak, and is referred to as implantation bleeding.
It is important to remember that not all women will have implantation bleeding. Some will bleed a very small amount, other might have a heavier flow. It is also possible to feel light cramping in the uterus as well.
If you experience any heavy bleeding with clots, or painful cramping, you should contact your doctor immediately. If you feel pain on either the right or left side of your lower abdomen that does not go away, this could mean the egg as implanted within your fallopian tube and needs to be addressed as soon as possible.
Sugihara, Kazuhiro , and Daijiro Sugiyama. “Trophoblast cell activation by trophinin ligation is implicated in human embryo implantation.” National Center for Biotechnology Information. National Institute of Health, n.d. Web. 17 Apr. 2010. www.ncbi.nlm.nih.gov/pmc/articles/PMC1805454/pdf/zpq3799.pdf.
Harville, EW. “Vaginal bleeding in very early pregnancy.” Human Reproduction 18.9 (2003): 1944-1947. Pub Med Central. Web. 17 Apr. 2010.
“Ectopic pregnancy – Overview.” University of Maryland Medical Center. N.p., n.d. Web. 16 Apr. 2010. http://www.umm.edu/ency/article/000895.htm.