Prenatal and neonatal exposure to smoking negatively affects hearing. The risk of hearing impairment doubles if exposure occurs both before and after delivery. This is what emerges from a Japanese research led by Dr. Koji Kawakami of the University of Kyoto. The study was published in the journal Paediatric and Perinatal Epidemiology.
The researchers examined data from 50,734 newborns. 3.8% of them had been exposed to smoking during intrauterine life. 3.9% had suffered passive smoking in the first months of life. 0.9% had been exposed both prenatally and neonatal. In 12.5% of cases, however, the future mother had quit smoking as soon as she found out she was pregnant.
The analyzes showed a link between hearing problems and smoking during pregnancy. At the age of three, children exposed to smoking in their mother's womb were 68% more likely to have hearing problems. The percentage dropped to 30% more in the case of children exposed to passive smoking only in neonatal age. In the case of ex-smokers mothers, the probability was 26% higher than average. On the other hand, children exposed to smoking in both phases were 2.4 times more likely to experience hearing problems within 3 years.
The results of the study show the importance of quitting smoking before planning a pregnancy, as well as during and after. Many expectant mothers stop smoking when they discover they are pregnant. Although this is an important step, it may not be enough.