What happens durning the first trimester

A baby develops rapidly during the first trimester. The fetus begins to develop a brain and spinal cord, and the organs begin to form. The baby's heart will also begin to beat during the first trimester. Arms and legs begin to bud in the first few weeks, and by the end of eight weeks, fingers and toes start to form.

The first trimester is the time in between fertilization of the egg by the sperm (conception) and week 12 of a pregnancy.