When does a fetus have a brain?

Researchers began studying the theory of baby brain because women frequently report cognitive changes, particularly forgetfulness, during pregnancy and shortly after becoming mothers. Studies examining the relationship between pregnancy or the early stages of motherhood and changes in a woman's ability to think, however, have produced conflicting results. read more

Third trimester: Baby's brain grows. The third trimester is brimming with rapid development of neurons and wiring. Baby's brain roughly triples in weight during the last 13 weeks of gestation, growing from about 3.5 ounces at the end the second trimester to almost 10.6 ounces at term. read more

At this point the fetus is able to react to external stimuli, which is held as the standard for life. Week 20. Although the fetus can move at week 14, the movements are little more than jerky reflexes. They are not driven by higher cortical functioning. read more