By the end of 3 months, organs have developed. During the last 6 months of pregnancy organ systems continue to refine themselves, but specialization of cells and growth in size become the main thrust of the process underway. At the end of nine months the incredible events are complete. A child is born. The fertilized egg multiplies into many cells.
Some cells develop into the embryo and some cells develop into the placenta.
About 8 days after fertilization the embryo will attach to the uterus lining. Tiny buds form which will later develop into arms and legs. 2nd Month All of the major organs are forming. The embryo's heart is pumping blood. The head is relatively large compared to the rest of the body and brain development is well underway.