What a cutie!
This week baby begins to form facial features. Their eyes are wide open and the lenses are forming. In an ultrasound, you can already see their ears and nose [1].
The nervous system of the baby is rapidly developing. Their brain has separated from the spinal cord, and the cerebellum and medulla oblongata are now formed. Also, the structure of nerve cells is becoming more complex [1]. This allows the baby to increase their activity — waving their arms and legs.
Sexual glands continue to develop. In boys, the testicles form [2]; in girls, their lifetime supply of eggs develops [3].
The heart transitions from two chambers to four. During an ultrasound, you will be able to hear the heartbeat [4].
During this week, internal organs continue to develop: the stomach takes its place and starts to produce gastric juice, and the kidneys also begin to function. The primary intestinal loop forms and the umbilical cord develops.
What we can see on an ultrasound
In the photo, you can see a tiny embryo in an oval-shaped amniotic sac. Though the baby is already moving, mama will not yet feel any kicks or flutters. The baby’s head, arms, and legs are labeled.
You will notice the head is larger than the body. Like the baby’s neck, its body is also starting to straighten. In the image, this is marked by the black dotted line.
The forming arms are visible. On the left side of the body, near where the arms fold over the baby's chest, you can see a small dark dot — it is the heart.
A yolk sac is visible next to the leg, appearing as a lighter ring with a dark middle. The baby’s nutrition and activity at this early stage of development are all supported through the yolk sac. The presence of the yolk sac indicates that the pregnancy is developing correctly.
