Smoking during pregnancy can cause hearing loss in baby: Study

Children exposed to tobacco smoke before and after birth may be at the risk of hearing impairment, a study of young children in Japan has found.

In the study of 50,734 children aged 3 years who were born between 2004 and 2010, researchers at Kyoto University in Japan exposed 3.8 per cent children to smoking only during pregnancy while 15.3 per cent were exposed in utero to only maternal past smoking.

Abut 3.9 per cent children were exposed only to second-hand smoke at 4 months, and 0.9 per cent were exposed to tobacco smoke during pregnancy and at 4 months.

"Although public health guidelines already discourage smoking during pregnancy and in front of children, some women still smoke during pregnancy and many young children are exposed to second-hand smoke," said Koji Kawakami from Kyoto University.

The prevalence of hearing impairment at age 3 years was 4.6 per cent, according to the study published in the journal Paediatric and Perinatal Epidemiology.

Compared with children not exposed to tobacco smoke prenatally and at 4 months, children exposed to only maternal past smoking during pregnancy had a 26 per cent increased relative risk of hearing impairment and children exposed to only second-hand smoke at 4 months had a 30 per cent increased relative risk.

Children exposed to only smoking during pregnancy had a 68 per cent increased relative risk, and those exposed to smoking during pregnancy and second-hand smoke at 4 months had a 2.4-times increased relative risk.

"This study clearly shows that preventing exposure to tobacco smoke during pregnancy and postnatally may reduce the risk of hearing problems in children," said Kawakami.

"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 said.