Both maternal obesity and underweight have neurocognitive consequences for children, according to a study of 535 10-year-old children who had been born at an extremely low gestational age. Details of the investigation include the following:

• Maternal prepregnancy obesity was linked to lower verbal IQ scores and poor scores on tests that measure processing speed and visual fine motor control.
• Children whose mothers had gained too much weight during pregnancy were also more likely to have lower scores on a test that assessed oral and written language.
• Children born to mothers who didn’t gain enough weight scored poorly on scales that measured oral and written language skills and reading.