Pregnancy 4 Weeks
Fetal Development
The morula has continued to divide and now consists of hundreds of cells. The structure is now known as a blastocyst. As soon as blastocyst gets to the uterus, it will embed itself into the endometrium (uterine lining), a process called implantation. It takes about 6 days for implantation to complete.
About 8 to 10 days after conception, the baby starts to produce Human Chorionic Gonadotropin, or HCG for short. These hormones prevent your next menstrual period from coming, allowing the baby to safely develop. It's these hormones that are used to detect pregnancy in a Home Pregnancy Test.
A minority of women experience a small amount of bleeding as their baby embeds itself into the endometrium. Implantation bleeding can be noticed around the same time as the expected menstruation. It therefore is often confused with having a period. Implantation bleeding is usually less and of a different color than a normal period.
The endometrium will provide vital nutrients to the developing embryo and will remove it's wastes. Once settled in, the blastocyst begins to split in two groups. One group of cells will become the placenta, and the other group will become the embryo.
