WebMD
Font Size
A
A
A

Implantation of the fertilized egg

About 6 days after fertilization, the egg has become a hollow ball of cells (blastocyst), which implants on the inside wall of the uterus (endometrium). After implantation, the blastocyst begins to develop into the:

  • Embryo (the group of cells that will become the fetus).
  • Sac that contains the embryo (the amniotic sac).
  • Placenta, which allows oxygen and other substances to pass from the mother's blood to the embryo or fetus. The placenta also allows wastes to pass from the fetus to the mother's blood and then to her kidneys for elimination.
Author Shannon Erstad, MBA/MPH
Editor Kathleen M. Ariss, MS
Associate Editor Pat Truman
Primary Medical Reviewer Renée M. Crichlow, MD
- Family Medicine
Specialist Medical Reviewer Kirtly Jones, MD
- Obstetrics and Gynecology
Last Updated November 30, 2006

WebMD Medical Reference from Healthwise

Last Updated: November 30, 2006
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
@ 1995-2007, Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.