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Week 3

Congratulations! You have conceived, although you probably don't know it yet. Your baby is currently just a small group of cells, but in just a few short weeks it will have become a fully formed baby. It is growing and multiplying at an unbelievable speed. Currently it is only the size of the head of a pin.

The Amazing Journey
The journey from egg and sperm to a baby is a miracle in it's itself. During intercourse, over 150million sperm are released. Of that, only about 200 ever make its way to the egg, which has been released from the ovary into the fallopian tube. Many women are mistaken in thinking that fertilization happens in the uterus, but it actually occurs in the fallopian tube. Once the sperm comes in contact with the egg, it has to penetrate through two layers of the egg. Several sperm may get through the outer layer (corona radiata) but usually only one makes it through the inner layer (zona pellucida). Once the sperm penetrates through and unites with the egg, membranes enclose them into one sac and changes the outside layer of the egg so no more sperm can enter and intrude. The sperm and egg then begin to share information and chromosones.

While the sex of your baby won't be seen for many weeks, it is determined in this very early stage. The sperm is the one that determines what you will have. Men have both male and female sperm. A male sperm will carry a Y-chromosome and produce a boy. A female sperm carries an X-chromosome and will produce a boy. The egg only contributes Y chromosomes. The next week will involve this newly formed group of cells traveling through the fallopian tube and into the uterus where they will implant. Implantation can cause mild cramping and sometimes light bleeding. This is where your baby will live for the next 9 months (37 weeks) of your pregnancy.