The Germinal Stage

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Within just a few hours after conception, the single-celled zygote begins making a journey down the fallopian tube to the uterus where it will begin the process of cell division and growth. The zygote first divides into two cells, then into four, eight, sixteen, and so on. Once the eight cell point has been reached, the cells begin to differentiate and take on certain characteristics that will determine the type of cells they will eventually become.

As the cells multiply, they will also separate into two distinctive masses: the outer cells will eventually become the placenta while the inner cells will form the embryo.

The next task is for the outer cells to implant themselves into the uterus. Implantation occurs when the cells nestle into the uterine lining and rupture tiny blood vessels. The connective web of blood vessels and membranes that forms between them will provide nourishment for the developing being for the next nine months. Implantation is not always an automatic and sure-fire process. Researchers estimate that approximately 58 percent of all natural conceptions never become properly implanted in the uterus, which results in the new life ending before the mother is ever aware she is pregnant.

When implantation is successful, hormonal changes halt a woman's normal menstrual cycle and cause a whole host of physical changes.

For some women, activities they previously enjoyed such as smoking and drinking alcohol or coffee may become less palatable, possibly part of nature's way of protecting the growing life inside her.

Learn more about prenatal development:

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