At the doctor's office a device is placed on dawn's stomach and she can hear her unborn child's heartbeat at five weeks gestation. dawn's unborn child is in the stage of prenatal development.

The fifth week of pregnancy is considered part of the embryonic stage of prenatal development.

During this stage, the embryo continues to grow in size, the placenta and the amniotic fluid begins to form, and the mother experiences several hormonal changes as a response to the embryo's implantation into the uterus of the mother. 

The embryo's cells begin forming specialized functions in a process called differentiation. The baby's heart, spinal cord, and brain begin to develop, so as his/her blood cells, kidney cells, and nerve cells. His/her external physical features also begin to form. 

The embryonic stage ends at the end of the 10th or the beginning of the 11th week of pregnancy, where the developing baby is now called a fetus.