NEW YORK (PIX11) -- There's finally a possible explanation for SIDS, or Sudden Infant Death Syndrome.

Babies that die unexpectedly have underlying brain-stem abnormalities that are not normal before death, according to new research published in the December issue of Pediatrics.

The brain stem affects breathing, heart rate, blood pressure and temperature during sleep. Experts say these abnormalities prevent sleeping babies from waking up when they rebreathe too much carbon dioxide, when they don't get enough oxygen or become overheated.

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Even infants who were sleeping face down or next to an adult had these underlying brain-stem abnormalities.

What this means is that parents can finally let go of some of the guilt that they did something wrong..And doctors can now try to identify tests for healthy babies to see who's at risk, and develop appropriate treatments.

In the meantime, safe sleep practices like a firm mattress could make a difference -- no padding, stuffed animals or pillows. And putting your baby to sleep on his or her back can help. Also, don't overheat your child. and don't put covers over the head.