Babies who die of sudden infant death syndrome are found with their heads covered about 25 percent of the time, according to two new studies.

Based on the findings of the studies, researchers believe head coverings may contribute to SIDS.

The conclusion of the studies supports recommendations to avoid head coverings to reduce the risk of SIDS, lead author Dr. Edwin A. Mitchell of the University of Auckland in New Zealand and colleagues noted in the medical journal Pediatrics.

For the two studies, researchers analyzed data from 393 SIDS cases from 1987 to 1990 in New Zealand and from 333 cases in a German SIDS case-control study from 1998 to 2001.

The studies found that 15.6 percent of infants in the New Zealand study and 28.1 percent in the German study had their heads covered at the time of their deaths.

Infants whose heads were covered often were sweaty, which suggests the covering occurred before death, the studies found.

Older infants were more likely than younger ones to have their heads covered, which probably reflects motor development, researchers said.

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