Researchers found that brain areas involved in movement developed at the fastest pace while those associated with memory grew more slowly.
Scientists say collating this data may help them identify early signs of developmental disorders such as autism.
Led by scientists at the University of California, researchers scanned the brains of 87 healthy babies from birth to three months.
They saw the most rapid changes immediately after birth - newborn brains grew at an average rate of 1 per cent a day. This slowed to 0.4 per cent per day at the end of the 90-day period.
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They found the cerebellum, an area of the brain involved in the control of movement, had the highest rate of growth - doubling in size over the 90-day period.
The slowest region measured was the hippocampus, a structure that plays an important part in how memories are made, 'BBC News' reported.
Looking at babies who were born early, researchers noticed their brains were 4 per cent smaller than the brains of babies born at full term.
Despite growing at a quicker rate than babies born on time, their brains were still 2 per cent smaller at the end of three months.