At five weeks, changes in the body are still subtle, and the embryo is still tiny. Even though the embryo is still small-scale, it’s developing quickly. Actually in pregnancy at week 5, now the embryo is the size of a sesame seed. The embryo is around 0.08-0.1 inches (2-3 millimeters)long.
The embryo is changing and growing rapidly, and many structures are starting to take place.
The placenta, amniotic sac, and umbilical cord are still forming. For now, the embryo is surrounded by the gestational and yolk sacs, which provide protection and nutrients.
The embryo is made up of three different layers at this point. These layers will develop over the next few months to form the baby’s organs.
Here’s a description of each of the layers ;
The ectoderm is the outer layer, it will become the outermost layer of skin and form the nervous system, ears, and eyes.
The mesoderm is the middle layer of the embryo, and it will form the baby’s heart and cardiovascular system, bones, and much of the reproductive system, muscle, ligaments, and kidney.
The endoderm is the inner layer of the embryo, and it will become the lungs, early urinary system, and gastrointestinal system.
One of the first things the embryo develops is the nervous system.
First, the embryo develops nerve cells that roll up into a tube and eventually close. This is called the neural tube, and it eventually becomes the baby’s brain and spinal cord. This is an important time of development for the embryo. Taking a folic acid supplement every day can reduce the risk of problems with neural tube development.
If you are taking prenatal vitamins, they should contain folic acid. If big prenatal vitamins make you nauseous, talk to your health care provider about taking only folic acid for a few weeks until you feel better. Folic acid pills are small and shouldn’t bother your stomach as much.
The embryo’s heart is also starting to take shape. Before the heart fully forms, there are two channels that have started to beat .In In the following weeks, these channels will merge and form a fully functioning heart.