The baby is well protected
At this time, the embryo looks like a C-shaped tadpole, and the amniotic membrane has formed and will protect the growing baby throughout the pregnancy.
Even though the baby is tiny, the first blood vessels are already forming to create the circulatory system. Heart tubes develop to form a two-chamber heart, with one ventricle and one atrium. By the end of the week, the baby’s heart will begin to beat [1].
The central nervous system also begins to develop: segments of the brain and spinal cord form from the central neural tube and the brain forms cerebral vesicles that will grow into the left and right hemispheres.
The endocrine system is also developing, beginning to form the thyroid, parathyroid, and anterior pituitary glands. The basic structures of the respiratory and digestive systems begin to develop this week, along with the trachea, lungs, liver, and pancreas.
Dimples start to form where the baby’s ears will develop.
What we can see on an ultrasound
In this photo, the contour of the growing uterus is outlined. The baby appears as a tiny tadpole floating in the amniotic fluid. The brain appears as two white dots, which will grow into the right and left hemispheres. The little white dashes at the top and bottom are the beginnings of the baby's arms and legs.
The small dark spot is the baby’s developing heart.
