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Baby Brain Development

Development of baby brain is an interesting and complicated procedure that takes place over a course of nine months. Read on to know all about this development...
Pregnancy is an exciting time for any mother-to-be. This is the time when a whole new life grows inside of a person. One of the most exciting parts of pregnancy is baby brain development. It's really exciting to understand how baby brain growth and development occurs over a course of nine months. This is a slow and systematic process that takes place all through pregnancy. This is also the time when the baby is very susceptible to developmental disorders related to the brain and to other parts of the body. This can occur due to either an improper diet, trauma or may even occur if the mother takes drugs or medicines that are contraindicated in pregnancy. Genetics and hereditary disorders also have a vital role to play in the development of a baby's brain. Given below are details regarding the baby brain development stages according to week wise progression of pregnancy.

Baby Brain Development Timeline

Weeks Development
Week 1 - Week 2 Conception, that is fertilization and attachment of the fertilized egg in the uterine wall.
Week 3 It is in the third week that actual organ formation begins, even though it is still considered to be an embryo. The backbone, cardiovascular system and the brain begins to form.
Week 4 The three parts of the brain, that is, the fore brain, middle brain and hind brain start forming. The optical stalk also forms.
Week 5 While the baby's brain development during pregnancy continues, other organs, like the circulatory system are activated. The facial features begin to develop and the arms, legs and digits are visible on the ultrasound.
Week 6 In this week, there is formation of brain hemispheres. Some amount of brain wave activity is also seen. The neural tube that connects the brain with the spinal cord closes in this week.
Week 7 The neurons in this week are multiplying at a rapid rate, thus, the brain is growing at a rapid rate. Its formation is nearing completion.
Week 8 By the eighth week, the head is quite large when compared to the rest of the body. The baby brain development activities reach a new high when there is further development of the hind brain, which is the center responsible for regulating vital activities, like the heartbeat, breathing rate, etc.
Week 9 The nervous system is developed and is ready for proper functioning at a basic level.
Week 10 The baby's brain development in the womb increases in its rate at this stage and the brain is forming around 250,000 neurons per minute. The genitals also begin to develop at this stage, thus, establishing the sex of the fetus.
Week 11 The spinal cord is clearly developed and defined and the spinal nerves start to stretch out to reach other parts of the body from the spinal cord.
Week 12 The brain enlarges in size only slightly as compared to its birth size and shape.
Week 13 This week marks the completion of the first trimester. The heart, spleen and liver are already functioning at this stage.
Week 14 At this stage, the baby is acquiring lots of nutrition for the brain development via the placenta.
Week 15 The baby's torso is growing rapidly and it gets completely covered by lanugo (very fine hair that protects the skin). The sense of hearing also gets sharpened in this week.
Week 16 The baby starts tugging at the umbilical cord at this stage.
Week 17 By the seventeenth week, the uterus begins to expand to give room to the growing fetus. As the skeletal system begins to grow and become hard, the nerves need protection. The spinal cord is protected by a barrier made of myelin.
Week 18 While the brain is growing very rapidly, the baby develops sensitivity to light.
Week 19 In this week, the fore brain develops into the left and right cerebral hemispheres. The brain is capable of forming millions of motor neurons, thus, enabling the baby to develop and make the muscle movements voluntarily. The nerve cells required for processing all the senses also start to develop rapidly.
Week 20 Nerve cells at this stage begin to make complex connections with the brain and the rest of the body, in the form of sensory perceptions. This goes on till the child grows up till the age of five years.
Week 21 The overall growth and cell multiplication rate of the fetus slows down considerably in this week. The heart is getting stronger and fat starts to get stored in the baby's body.
Week 22 As the brain tries to understand complex sensory perceptions, the fetus is now able to distinguish between different sounds.
Week 23 The nervous system is almost completely formed at this stage. All the nerve cells formation is complete, and all these neurons come together to form the nervous system.
Week 24 At this stage, the brain begins to regulate all the body functions and activates the visual and auditory systems. This heightens the overall senses of the baby.
Week 25 The spinal cord begins to straighten out and harden. The optic nerve at this stage can perceive light coming from any direction.
Week 26 The brain up till this stage of the baby brain development was smooth in its structure. However, at this stage, the tissues of the brain begin to develop creases. The brain waves also begin to get stronger at this stage, as there is heightened functioning of the auditory and visual sensors.
Week 27 As the brain is actively processing all the sensations it receives, it is claimed that may be the baby gets dreams at this stage. The brain tissues are rapidly developing now.
Week 28 The brain at this stage can regulate breathing rate and the body temperature. The brain continues to develop creases and fissures.
Week 29 - Week 40 The third trimester is marked by fewer brain developments. The size of the brain continues to grow without multiplication of neurons. The brain and lungs are the last organs to develop completely.

There are many conditions that can adversely affect the developing brain, like any kind of trauma or even malnourishment. Thus, it is of utmost importance that the mother takes immense amount of care during pregnancy so as to ensure that the fetus brain development takes place properly.
By Dr. Sumaiya Khan
Last Updated: 10/5/2011
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