Cases of porencephaly and global atrophyof the temporal lobe were highly related to prenatal or perinatal insults including preterm delivery and asphyxia.
The research team found that only three countries -- Croatia, Ecuador and Estonia -- had a decrease in their preterm birth rates between 1990 and 2010.
And although the rate of preterm births in the U.S. has dropped to 11.5 percent, it's still the highest rate of preterm births in any industrialized country.