Toggle: English / Spanish
During the first 12 hours after conception, the fertilized egg cell remains a single cell. After approximately 30 hours, it divides from 1 cell into 2 and 15 hours later, the 2 cells divide into 4. And at the end of 3 days, the fertilized egg cell has become a berry-like structure made up of 16 cells. This structure is called a morula, which is Latin for mulberry.
The cells continue to divide 8 or 9 days following conception into a blastocyst. Although it is only the size of a pinhead, the blastocyst is composed of hundreds of cells. The blastocyst is slowly carried by tiny hair-like projections in the fallopian tube called cilia toward the uterus. During the critically important process of implantation, it must attach itself to the uterine lining where it will be able to get nourishment from the mother’s blood supply. If the blastocyst is unable to attach, the pregnancy will fail to survive.
- Last Reviewed on 11/20/2012
- Irina Burd, MD, PhD, Assistant Professor of OB/GYN and Neurology at Johns Hopkins University School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2013 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
This page was last updated: June 27, 2013