According to the researchers, babies who were exposed to smoking during pregnancy had a 68 percent increased relative risk of developing hearing problems.
‘The hearing loss is raised up to 68 percent if the baby is exposed to tobacco smoke during and after pregnancy
"This study clearly shows that preventing exposure to tobacco smoke during pregnancy and postnatally may reduce the risk of hearing problems in children," said Koji Kawakami from the Kyoto University in Japan.
The study, published in the journal Pediatric and Perinatal Epidemiology, included data from 50,734 children aged three years.
Out of the group, 3.8 percent were exposed to smoking only during pregnancy, 3.9 percent were exposed only to second-hand smoke at 4 months, and 0.9 percent were exposed to tobacco smoke during pregnancy and at 4 months.
The results showed that the prevalence of hearing impairment among babies aged three who were exposed to smoke was 4.6 percent while those exposed to only second-hand smoke at 4 months had a 30 percent increased relative risk.
Children who were exposed to tobacco smoke during pregnancy and second-hand smoke at 4 months had 2.4 times increased relative risk.
"The findings remind us of the need to continue strengthening interventions to prevent smoking before and during pregnancy and exposure to second-hand smoke in children," Kawakami added.