The seventh week is a period of additional intensive development that differentiates the baby’s physical appearance. By the close of the seventh week, the baby will be about 13 millimeters. It is at this week that the baby’s ‘tadpole’ shape starts changing so that it starts taking a more recognizable outlook.
The buds (arms and legs) that started growing in the sixth week advance more to become more elaborate. The fingers in each hand are starting to separate and several notching can be seen in a digital ray. In the foot bud, the ankles and toes start emerging with primary muscles appearing as joined and elongated cells.
The facial features become more elaborate as mouth and tongue start forming. However, these are only visible through an ultrasound scan because they are fully covered. Notably, the sense of taste develops concurrently with the growing mouth and tongue. Besides, the retina that started to form earlier extends forward so that the lenses become visible in the eye socket. Because the eyes have very differentiated features, more cells are seen developing rapidly and concurrently by the close of week seven.
The immune system continues to mature by the 7th week. Every new part that develops after the seventh week has more antibodies from the baby’s lymph system. Experts indicate that by the close of week seven, the antibodies can spring into action in case that of the mother is weakened. It works closely with the developing liver to remove toxins and have them removed through the umbilical cord.
While the baby’s heart started to form and beat in the last two weeks, it begins pumping some blood by the end of the seventh week. Though the circulation is primitive and is greatly assisted by the mother’s system via the umbilical cord, the heart is actually pumping blood through microtubules connecting already developed organs especially the brain and spinal cord.
At the seventh week, the baby is still very small to show significant bodily changes. However, mothers can really feel it because everything is working to keep up with the fast-growing body. Therefore, you should expect to see the following changes.