Early Pregnancy, Weeks 3 and 4

You have probably not noticed anything different yet.  Some women do complain of a strange metallic taste in their mouth right about now though.

The fertilized egg has arrived in your uterus.  It has embedded itself in the uterine lining.  It is nourished from blood vessels in the lining of the uterus.  The placenta begins to form around it.  Even before you may know that you are pregnant, the baby's central nervous system, heart, and lungs start to develop.  The tiny little heart begins to beat.

By the end of the 4th week, the baby is about 3/16 of an inch long.  Although distinct facial features cannot yet be seen, the face is beginning to form and dark circles mark where the eyes will be.