At 3 to 5 weeks in the womb What is the baby doing?

3 weeks- At three weeks pregnant, you most likely don't even know that you are pregnant. All that is present is about 500 microscopic cells. The cells haven't formed an embryo or fetus yet. This is when the zygote (the microscopic cells that aren't yet formed into an embryo/fetus) implants itself into your uterine lining.

4 Weeks-Well at four weeks pregnant, the embryo has just now implanted itself. The fetus has not yet developed any limbs or any obvious features yet. It is about 1/25" and weighs less than one gram. This is probably the week you will find out you are pregnant. This week the placenta is being created, as well as the umbilical cord and the baby is now working on developing actual features. The embryo is now made of three layers that will develop into functioning organs.

5 weeks- There have been some HUGE changes from week 3 to week 5! Congratulations, your fetus is starting to actually look like a fetus! It now is beginning to develop little stubby limbs and a little head. It is about 2 millimeters and still weighs less than one gram (about the size of a poppy seed). This is the week your baby will develop its heart beat which will in turn means your baby also has blood circulation and it's first functioning organ! The placenta and umbilical cord are still developing at this point. Also at this week the beginning of the brain, cardiovascular system, nervous system and reproductive system are in the making!