can lfe sound waves hurt my unborn babys hearing?????????? [Archive] - Audio & Video Forums


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05-18-2005, 04:49 PM
does anyone know if lfe sound waves can hurt my unborn babys hearing? THANK YOU.

05-18-2005, 05:17 PM
For anyone who wants to know I'm the dad , and it's a boy!

05-18-2005, 07:00 PM
For anyone who wants to know I'm the dad , and it's a boy!

Are you sure it will be a boy? I read somewhere that excessive LFE's could change that.

I think it was in the National Enquirer...., yeah...


05-18-2005, 07:19 PM
yes I'm sure we just got an ultra sound,and thankyou.

05-18-2005, 11:02 PM
Did you hear this somewhere or is this just some random paranoia?

05-19-2005, 03:30 AM
I dunno...but the Brown Note episode of South Park is on again tonight here...

There are so many sub 20 Hz frequencies that occur inside a mothers body that I'm reasonably confident nothing negative will come of this. We're exposed to subsonic sounds all the time...WE CAN'T HEAR THEM though..
Relax, the worst thing that can happen is your baby boy growing up to be a bass-head or play soccer.

05-19-2005, 05:20 AM
I wouldnt be concerned about LFE as much as i would be with highs.

05-19-2005, 07:05 AM
does anyone know if lfe sound waves can hurt my unborn babys hearing? THANK YOU.


The fetus responds to sounds quite early in development. I'm clipping some text below taken from peer-reviewed scientific journals. Most relevant to your question is this text quoted from a recent scientific article, NeoReviews Vol.6 No.3 2005 e141 (Authors: Robert E. Lasky, PhD, Amber L. Williams)

INTENSE NOISE. Few epidemiologic studies have investigated the relationship between fetal noise exposure and hearing loss in humans. Several studies report small but consistent effects, although these investigations have been criticized on methodologic grounds, especially for the failure to include adequate control groups. (29) It seems likely that the uterine environment buffers the fetus from insult, but if noise is excessively loud and of a long duration, damage to the cochlea results. Exposing pregnant ewes multiple times to 16-hour 120-dB SPL broadband noise resulted in modest IHC and OHC damage in the middle (mid frequency) and apical (low frequency) turns of the cochleae of the exposed fetuses. (30) Postnatally, damage is more extensive, targeting the basal (high frequency) turn of the cochlea. These results highlight differences between uterine and terrestrial hearing. High-frequency sounds that are emphasized postnatally by the resonance characteristics of the outer and middle ears are attenuated by maternal tissue in utero.

Then in another section the article addresses sound in NICU's (neonatal intensive care units). Clearly not a fetus at this point.

The NICU Sound Environment: For decades there has been concern that excessive noise levels in NICUs adversely affect long-term outcomes in high-risk infants. (67) Infants frequently are exposed to noise levels of 55 and 75 dB(A) SPL, comparable to the noise produced by a vacuum cleaner. Impulsive noises in the NICU reach well over 100 dB(A), (68) comparable to the noise produced by a power mower.

Although NICU noise levels are greater than recommended by the American Academy of Pediatrics (AAP) and greater than in intrauterine or home environments, they are below those known to induce hearing loss in adults. (69) However, it is unlikely that noise thresholds that induce hearing loss in adults apply to newborns for at least three reasons: 1) there are striking developmental differences in the sound energy transmitted into the cochlea due to growth and development of the outer and middle ears, as reviewed previously; 2) the cochlea (the site of lesion for noise-induced hearing loss) is maturing structurally and functionally while the preterm infant is in the NICU; and 3) the preterm infant experiences a variety of ototoxic exposures in the NICU. At this time, definitive research that addresses whether NICU noise levels result in hearing impairment is lacking.

But aside from just being concerned about damage to fetal hearing, you should also be aware that the fetus does respond to sound very early. The last line of the following quote should also give concern about LFE. I couldn't get access to the full text to see exactly what evidence was cited for that comment.

From: Archives of Disease in Childhood - Fetal and Neonatal Edition, Vol 71, F81-F87

Previous research has revealed that the human fetus responds to sound, but to date there has been little systematic investigation of the development of fetal hearing. The development of fetal behavioural responsiveness to pure tone auditory stimuli (100 Hz, 250 Hz, 500 Hz, 1000 Hz, and 3000 Hz) was examined from 19 to 35 weeks of gestational age. Stimuli were presented by a loudspeaker placed on the maternal abdomen and the fetus's response, a movement, recorded by ultrasound. The fetus responded first to the 500 Hz tone, where the first response was observed at 19 weeks of gestational age. The range of frequencies responded to expanded first downwards to lower frequencies, 100 Hz and 250 Hz, and then upwards to higher frequencies, 1000 Hz and 3000 Hz. At 27 weeks of gestational age, 96% of fetuses responded to the 250 Hz and 500 Hz tones but none responded to the 1000 Hz and 3000 Hz tones. Responsiveness to 1000 Hz and 3000 Hz tones was observed in all fetuses at 33 and 35 weeks of gestational age, respectively. For all frequencies there was a large decrease (20-30 dB) in the intensity level required to elicit a response as the fetus matured. The observed pattern of behavioural responsiveness reflects underlying maturation of the auditory system. The sensitivity of the fetus to sounds in the low frequency range may promote language acquisition and result in increased susceptibility to auditory system damage arising from exposure to intense low frequency sounds.

And this graph of sensitivity threshold vs frequency for different fetal stages, lifted from figure from the NeoReviews article. I don't know if the link will work, you may need a subscription, I'm not good at this.. If someone can host the image I can send the jpg. Its a direct link, sorry about the size.

Again congrats on the baby! Take care of Mom!

05-19-2005, 10:05 AM
does anyone know if lfe sound waves can hurt my unborn babys hearing? THANK YOU.

Interesting question and also CONGRATS! It's great to be a dad. Just wanted to pass on a recent incident.

My teenage son's band was practicing the other night - drums, guitar and bass. Their practice room was relatively small with finished pine ceilings. Lots of noise! My brother and his wife were there and came in to here a couple of songs the band had perfected, so to speak. They're expecting in late June. It didn't take long for the baby to start kicking and moving around. I'm no expert, but it seemed obvious to us that the baby was responding to the music. We all thought it was cool!

05-19-2005, 05:00 PM
We just had our third, all girls, and they can all hear fine. The doctor demonstrated that sound is severely muffled by the abdominal wall, membranes and specifically the amniotic fluid. I think the physics imply that the movement of vibrations from one medium, air, to another medium, flesh and water basically, rapidly attenuates the sound. I wouldn't worry about it.

05-19-2005, 05:45 PM
Thank you everyone this has helped a lot. I guess I was just worring because It's my first baby and I dont want to be thinking that I'm making my baby loose his hearing.Buy the way this ? came about when my wife came in,and I was listning to some loud music, the baby started kicking and I thought the sound was hurting his ears.

05-19-2005, 05:54 PM
(sorry about that joke earlier)

We are also expecting in October and I asked our doctor about this. While he wasn't an expert on this, he did say that a lot of research has been done and is still being done on this very topic. He said that it wasn't the frequencies as much as the volume that we should be concerned about. While the amniotic fluid and the mother's body do muffle the sounds substantially, it is not a good idea to attend loud concerts when you're pregnant.

He also mentioned something interesting. Unborn babies learn to familiarize themselves with the sounds around them and will continue to gravitate towards these "sounds" after birth. So for example, a child will recognize his father's voice and "prefer" it over another man's. Likewise, a baby that has been exposed to a lot of television before birth, will be acclimated to this environment after birth. While this sounds amusing, there is a serious component to this. Commercial television and radio, for example, has a lot of choppy programming with frequent changes in volume and lots of short soundbites. There is some compelling evidence that this exposure both before and after birth contributes to short attention spans, ADD, hyperactivity, and other behavioral problems later in life. Lower volumes, quieter households and longer types of programming has been shown to reduce the instances of behavioral problems. Much of these conclusions, however, are still premature, but he believes that they have a lot of merrit.

So turning down the volume, especially when T3, Ryan Seacrest, Howard Stern, or Everybody Loves Raymond are on, is probably a good idea. And loud concerts are probably not a good idea, either.

Mr Peabody
05-20-2005, 06:54 PM
I'm not a doctor but I play one on TV, well actually I don't, but I would if given the chance. If being in the woom blocks sound it makes sense that the fetus would respond to lower frequencies because you feel low frequency in your body.

My daughter is pregnant and I was teasing her about putting my headphones on her belly, she told me that there is a product out like that. Causing harm never stopped anyone from putting out a product to make a buck but you'd think that maybe they done some research to make sure this wasn't dangerous. Then again you would have a difficult time proving any damage came from this product.

Sound is fascinating and what we know is hardly anything. There is a sound therapy that is used for behavior modification. You have to listen through headphones and have an exaggerated bass response. I listened to one of these CD's for a moment, that's all I could stand. The one I heard was regular music but it was like someone took one of the equalizer controls and pushed it all the way and back again very quickly.