New research from the University of Adelaide shows that weight gain and increased head size in the first month of a baby's life is linked to a higher IQ at early school age.
... babies who put on 40% of their birthweight in the first four weeks had an IQ 1.5 points higher by the time they were six years of age, compared with babies who only put on 15% of their birthweight.
Those with the biggest growth in head circumference also had the highest IQs.
"Head circumference is an indicator of brain volume, so a greater increase in head circumference in a newborn baby suggests more rapid brain growth," says the lead author of the study, Dr Lisa Smithers from the University of Adelaide's School of Population Health.
"Overall, newborn children who grew faster in the first four weeks had higher IQ scores later in life," she says.
"Those children who gained the most weight scored especially high on verbal IQ at age 6. This may be because the neural structures for verbal IQ develop earlier in life, which means the rapid weight gain during that neonatal period could be having a direct cognitive benefit for the child."