Remember that ball of cells we talked about during week three? That ball of cells is now an embryo, and has implanted in the uterine lining where it will stay until delivery time. Once it is firmly in place, that ball of cells divides into two groups. One half will become the actual baby, while the other half will become the placenta.
Your baby is officially an embryo. This precious embryo is about the size of a poppy seed, beginning to be surrounded by its amniotic sac. This fluid protects the baby as she grows. There is also what is called the yolk sac forming – this important part of the sac is what delivers nutrients to your baby. This yolk will eventually be incorporated into the digestive track as the baby develops. There are several layers of the embryo, three in fact, that each will develop into particular parts of the baby’s body.
The ball of cells is now splitting into the placenta and the embryo. You will likely be experiencing the classic symptoms of pregnancy at this stage, including a heightened sense of smell, and increased nausea. While many women don’t begin to experience morning sickness (which is not limited to the AM hours) until the 6th week, some will find that they are ahead of the game and are feeling sick and even vomiting a bit. Be sure that you start a pre-natal vitamin, if you haven’t already. You need higher amounts of folic acid while you are pregnant, usually 600mcg a day, but check with your physician before you start any medical regiment.