Add another hazard to the long list of reasons not to smoke during pregnancy: Children exposed to tobacco smoke in the womb may be at higher risk for hearing loss.
 

Researchers examined data from almost 1,000 children aged 12 to 15 who took part in the 2005 to 2006 U.S. National Health Examination Survey. They found that about 16 percent of them had been exposed to tobacco smoke while in the womb.
 

These adolescents had evidence of some overall hearing loss and were nearly three times more likely to have one-sided, low-frequency hearing loss compared to youngsters without such exposures, according to the study published online June 20 in the journal JAMA Otolaryngology -- Head & Neck Surgery.
 

The level of hearing impairment associated with fetal exposure to tobacco smoke was "relatively modest" at less than three decibels, wrote a team led by Dr. Michael Weitzman, of the NYU School of Medicine in New York City. "[However], an almost three-fold increased odds of unilateral hearing loss in adolescents with prenatal smoke exposure is worrisome," they wrote.
 

The study could not prove a cause-and-effect relationship between smoking during pregnancy and hearing outcomes in offspring, only an association. Two hearing experts, however, said they weren't surprised by the findings.
 

"This is an effect which has been described previously for the adult population, so it is logical that it would also apply to children of smokers," said Dr. Ian Storper, director of otology at the Center for Hearing and Balance Disorders at Lenox Hill Hospital in New York City.
 

Storper said the study "provides more reason to eliminate tobacco usage across our population and to continue research in the area to understand the mechanism of damage to the auditory system."
 

Dr. Martin Chavez, director of Maternal Fetal Medicine at Winthrop University Hospital in Mineola, N.Y., agreed, noting that fetal exposure to toxins "can have lifelong consequences."

The new study "proves that not smoking or avoiding being around others who smoke can [not only] increase the likelihood of a healthy newborn, but also decrease the chances of other diseases later on," Chavez said.