Features Overview
month 4
As mentioned in Month 3, the surface of the brain begins to show the development of gyri (the ridges) and sulci (the grooves).
But already, your baby's brain is directing the muscles involved in breathing (the diaphragm and chest muscles) to contract.
Myelination begins to appear on the axons of some neurons. This is the fatty sheath that surrounds neuronal processes and fibers, making neuron communication significantly more efficient. It is often referred to as the “white matter” of the brain.
At 16 weeks, the fetus resembles an infant. The eyelids formed in months 2 & 3 are now blinking; the heartbeat can be easily found; and nose, mouth, chin and ears are defined.
You can see the fingers and toes; they even have finger (toe) prints.
month 5
Myelination is consistently progressing, and will continue to do so until your child is a teenager.
By the middle of the 5th month, the baby moves its facial muscles and can suck its thumb (or finger) and yawn.
It is also moving around in the womb - which may be felt by the mother. This “quickening” is usually a subtle feeling, often described like a butterfly flitting its wings
By the end of the 5th month, your baby is reflexively swallowing amniotic fluid.
And since his/her taste buds have developed, he/she is also tasting..
…that brain is working hard to develop all the basic skill sets your baby will need by his/her time of birth.
month 6
Midway through the 6th month, your baby’s nervous system is developed enough for the baby to respond to sounds. This means that outside influences (sounds) will effect brain development, either positively or negatively.
Dolphin sounds have the greatest influence, but talking and music will also impact development. By the end of this month, your baby might turn his/her head towards the sound of your (or your partner’s) voice.
Additionally the baby's inner ear canals are developed by the end of this trimester. This has led to speculation that the baby is able to sense its position in the uterus.
So NOW you can communicate with your baby, in a way.
AND you are already teaching your child, for he/she is learning about sound, emotions, and more - developing the foundation for creating perception and belief.
If you are curious about what a fetal brain MRI looks like during the 4th, 5th, and 6th gestational months, click here.
To learn more, check out these websites:
The Urban Child Institute: Baby’s Brain
Very Well Family: Everything you need to know about fetal brain development
Colleen de Bellefonds: When does your baby develop a brain?