Hi
Can fetuses make audible sounds from inside the womb? Can their sounds be heard with the naked ear? What kinds of sounds are they? I haven’t been able to find any information on it.
davidmich
Sound requires air, as far as I know, so probably not.
no sound travels well through water, but don’t know about a fetus making any. I know it isn’t water but almost the same.
I wonder if their little guts gurgle as they generate meconium?
The fetal heartbeat can be heard.
The likely answer is no. The “gurgling” we hear in extra-uterine people is because of gas running through fluid. Fetuses don’t have a lot of reason to cry in utero, and even if they do, they’re not well-equipped to make noises that transmit from water (i.e. amniotic fluid) to air without another medium involved. Their heartbeats usually require a stethoscope in the olden days, or now an ultrasound.
Yet a fetus can hear external sounds it seems. Shouldn’t it also work the other way around? Please explain how that works.
davidmich
Er…why? We can see light, but that doesn’t mean we emit light. Some things work in only one direction.
Here’s a useful link. Most say no.
but this link
"Sound relies on a medium to transmit it. Liquids, being denser than air, are better at transmitting sound (and solids even more so); arguably if an infant in utero manages to clap hard enough then it could be heard outside the mother’s body.
Oh, and infants can cry in utero. My ex-wife is a nurse who has had OB/GYN experience; not only has she heard it happen, she could imitate it. Vocal chords vibrate just as easily in amniotic fluid as they do in air."
suggests it’s possible.
Thanks everyone.
Quite a few commenters on this Straight Dope link say fetal noises can be heard.
and here.
Discovery Channel Video Baby Cries in Womb
Gave me chills. They also look like they are breathing when in utero, which is pretty freaky but cool at the same time. I am thinking it is just a reflex, and unlikely that any actual sound is being produced, but still freaky to see
Th question is how it’s possible for noises to emanate from the womb.
davidmich
Why would it not be possible? As you’ve posted yourself, sound travels well in any sufficiently dense medium.
I get the sense that you think sound can only travel through air. That isn’t true (which, bizarrely, I just spelled “trough”). Sound is just compression of any medium, be in solid, liquid, or gas. Think about it this way–whales can and do call underwater with no problem. Whale-calls are “sound” just as much as Speaker-calls (usually to ladies) are. The gist is that if the fetus makes a sufficient noise, it would vibrate its amniotic fluid, then mommy’s tummy, and that vibration would make the air around mommy vibrate, too. Our ears would pick up the latter.
As to why we can’t hear it but they can’t hear us, it’s the fact that we’re much, much louder than a fetus. We have stronger muscles and are significantly larger.
Holy crap, that’s creepy.
Thank you Speaker of the Dead. That clarifies things much more.
davidmich
P3S. You don’t need to say everything twice.
It’s a Tapatalk default thing for some people, I’m finding out.
There are also boundary conditions - while it is true that denser mediums mean less energy loss and longer transmission, the boundary between two media makes it hard for sound to exchange. Thus if you drop a device playing music into water, you can hear it immediately get quieter and frequencies are distorted. If you stick your head in, you can again hear it, as the water is now pressing against eardrum and directly exchanging without a transition through air.
In the case of the fetus, there is the amniotic fluid, but the next boundary is the elastic uterus and stomach wall of the mother - which is less conducive to sound transmission. The only way you will hear anything is via a stethoscope, which is both in contact with the skin and acts as an amplifier (large contact patch, closed tube to the ear canal).