25 September 2000
Fetuses Hear At 30 Weeks
by Kate Melville
Listen up expectant dads: All those hours spent talking to your unborn child via your partner's burgeoning belly don't go unnoticed. New research from Queen's Faculty of Health Science proves that at 30 weeks the fetus is indeed able to hear and just might be listening to your muffled words of love.
Dr. Barbara Kisilevsky and her colleagues in Queen's School of Nursing have demonstrated for the first time that the human fetus can hear by the eighth month of pregnancy. Dr. Kisilevsky's findings, published in the August issue of the Journal of Early Human Development, give weight to the actions of many expectant parents and are in keeping with the physiological development of the auditory system.
"Although we know that the auditory system develops in the eighth month, there has never been proof that the fetus could actually hear inside the womb," says Dr. Kisilevsky. "Our study confirms that fact."
Dr. Kisilevsky and her colleagues studied 143 fetuses (91 low-risk pregnant women and 43 high-risk pregnant women) between 23 and 34 weeks of gestation. The fetuses' cardiac and body response to computer-generated white noise was measured using an ultrasound scanner. The findings indicated cardiac and motor responses at about 30 weeks.
"If we play sounds loudly - really loud - the 30-week-old fetuses will move to it, but we don't get any response prior to 30 weeks," says Dr. Kisilevsky. "What we still don't know is what they hear, or how clearly they distinguish various sounds."
Ultimately, says Dr. Kisilevsky, the team hopes to determine if what the fetus hears influences its development. "We suspect that the mother's voice, and what the fetus hears has an impact on its development - that it shapes the infant to prefer and recognize its native language. But we still don't know if your child will be brighter, for example, if you play music to it in utero, despite the notions disseminated in the popular media.
Today many entrepreneurs talk about "fetal universities," and sell devices that adhere to the abdomen and transmit music and information to the fetus. But is this trend based on good science?
"We don't know if women should be using these devices," says Dr. Kisilevsky. "We don't know what they should be playing, how long, or how loud." In fact, animal studies have shown that when audio or visual stimulation is provided to chicks in utero, there is a temporary delay in hearing when they are born.
"We don't think playing music will do any harm, but is playing Mozart helpful? Good science has yet to show that there is any benefit," says Dr. Kisilevsky.
So expectant moms, you can continue to stock up on classical music CD's, you just might not need to play them until the 8th month. Then again, as long as the ghetto-blaster isn't strapped to your belly, it can't hurt to play music throughout your pregnancy, and it may be your last chance to listen to Bach's Concerto in D Major in peace.