Tuesday, August 2, 2011

In the womb: Sensing the world outside

The ability to hear in utero appears around 23 weeks, as any pregnant woman in her second or third trimester can attest; if she sneezes, the baby jumps.

But if the same noise is repeated frequently, your baby will get used to it and stop responding. No need to worry — that's a sign that the brain is developing normally, says Lise Eliot, an associate professor of neuroscience at Chicago Medical School and author of What's Going On In There? How the Brain and Mind Develop in the First Five Years of Life.

Breathing underwater. Your baby begins to "breathe" while he's still in the womb, even though his lungs aren't taking in any oxygen, says Eliot. At around 27 weeks, his fluid-filled lungs will start to expand and compress due to the rhythmic contractions of your diaphragm and chest muscles, which help him develop the muscles and motor circuits necessary for actual breathing. So by the time your newborn takes his first gulp of real air, he'll have had plenty of practice.

Scent from beyond. Starting around 28 weeks, your baby can smell in the womb the same things that you're smelling outside. Some of the evidence about fetuses' sense of smell comes from preemies: In one study, peppermint extract was held under the noses of pre-term babies. Those younger than 28 weeks didn't respond, while the older ones reacted by sucking, grimacing, or moving away.

Your baby's sense of smell is actually enhanced by the amniotic fluid she's floating in, says Eliot, because we're better able to smell things after the odor molecules join with a liquid (like nasal mucus). During the third trimester, the placenta also lets odor molecules pass through it more easily. So when you order that vibrant smelling dish in your ninth month, your baby is taking in the aroma right along with you.

Christian Child Placement Service
http://www.facebook.com/Adoption.aChoiceforLife
1-800-553-2229

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