In the early and mid-1990s, studies at the University of California-Irvine found that listening to Mozart sonatas improved the spatial-reasoning of college students. People immediately jumped to the conclusion that classical music improves intelligence, and the earlier people started listening to it, the better. First mothers were urged to play music for their toddlers, then their newborns... then their fetuses. In fact, follow-up studies were unable to confirm the experiments' results in adults or children.

Then Dutch researchers found that not only can late-term fetuses "hear" sounds, but they can actually "learn." The researchers exposed the fetus to a noise, then used ultrasound to see how it reacted. They found the fetus reacted to the sound more quickly each time it heard it. But there's no evidence that this early "learning" has any effect on later intelligence, either.

So is there anything women can do during pregnancy to increase their babies' intelligence?

"The most important thing you can do to ensure a healthy baby and promote a healthy brain and mental abilities, is to have the healthiest pregnancy possible," says Lise Eliot, Ph.D., assistant professor of neuroscience at The Chicago Medical School, and author of What's Going on in There? How the Brain and Mind Develop in the First Years of Life.

For those who want more specifics, here are a few suggestions:

• Avoid smoking, drinking and drugs. All of these are known to impair neurological development.
  
  
• Gain enough weight for the baby to grow adequately. Obstetricians usually recommend women gain between 25 and 35 pounds. Too much weight gain can lead to a large baby and a difficult delivery, which can be risky to a new baby's brain. But not gaining enough weight is dangerous, too, since lower birthweight babies tend to have smaller heads and smaller brains, which has been linked with lower I.Q.
  
  
• Eat a well-balanced diet, and take a multivitamin, multimineral supplement. Dr. Eliot explains that there are 45 essential nutrients our bodies need, "and the vast majority of these are known to be necessary for neurological development."
  
  Some examples:
  • Iodine. Necessary for making thyroid hormone, which is essential for brain development. (Most women in the U.S. get plenty of iodine from iodized table salt.)
    
    
  • Iron. If a woman doesn't have enough iron, she can't make enough red blood cells to transport oxygen to the baby, affecting brain and body growth. That's why obstetricians monitor so closely for anemia.
    
    
  • B vitamins, including folic acid. Essential for fetal development, especially during the first month of gestation.

  
  
  

• Practice good hygiene to avoid viral infections. "A lot of viruses are very dangerous to the fetus even when the mother has no symptoms," says Dr. Eliot. She suggests pregnant women wash their hands frequently, avoid sharing food with toddlers and small children, and report any symptoms to a doctor. Pregnant women are now advised to get flu shots either before pregnancy or after the first trimester.
  
  
• Exercise. This one's surprising, but there's evidence that mothers who continue to work out during their pregnancy have smarter babies. James F. Clapp, M.D., of Case Western Reserve University in Cleveland, compared the children of pregnant women who continued to exercise throughout their pregnancy with the children of women who gave it up. He found that at five years of age, the children of the exercisers scored significantly higher on tests of general intelligence and language skills.
  
  If you do all this and still want to play classical music and read to your unborn baby, go right ahead. "It can't do any harm," says Dr. Eliot. "And maybe it even helps... in the sense that a mother who would take the trouble to read to or play music to her stomach is probably very motivated to take good care of her baby when it arrives!"
  
  
  Beth Weinhouse is a frequent contributor to Your Baby Today. She specializes in women's and children's health issues and lives in Oxford, Mississippi with her husband and 6-year-old son.