By this stage the foetus is now inhaling and exhaling amniotic fluid. All the raw materials are in place and the brain and spinal cord are growing at a rapid rate. At around 18 weeks, the asymmetrical tonic neck reflex emerges.
By 26 weeks the fetus is 14" long and almost two pounds. The lungs' bronchioles develop. Interlinking of the brain's neurons begins. The higher functions of the fetal brain turn on for the first time. Some rudimentary brain waves can be detected. The fetus will be able to feel pain for the first time. It has become conscious of its surroundings. The fetus has become a sentient human life for the first time.
At seven months, the fetus is 16" long and weighs about three pounds. Regular brain waves are detectable which are similar to those in adults.
The cerebral hemispheres now cover the whole top and sides of the brain including the cerebellum. Cerebellar development begins from this moment, but will not be complete until two years after birth. Six distinct layers are now differentiated within the cerebral cortex, and almost all of the neurons within the central nervous system are present by the end of this sixth month of life and neural 'circuitry' continues to develop.