Besides, the condition is so common in children under 6 that about eight out of 10 would have been infected with glue ear at least once in their childhood.

But many cases go undetected because its typical symptoms are mostly dulled hearing and mild earache, which can be easily overlooked, Gu says.

Li Zhen, a senior obstetric specialist with Chongqing Xinqiao Hospital, brings forward the choice of precautions to before a child is born.

Preconception medical checkup and preparation can help recognize and reduce the risks so as to have a healthy fetus, and prenatal care under medical instruction can largely reduce the possibility of unwanted health risks, including hearing loss.

In fear of cross infection or drugs' side effects, some mothers-to-be don't seek professional help when they catch a cold and fever. They self-medicate or do not take medicines at all. Both practices pose danger to the hearing development of the baby, Li says.

It is also very unwise to take Chinese herbs during pregnancy, because the chemicals and ingredients in Chinese herbs are usually unknown, and can be unsafe to the child, Li says.

Hu, president of the China Rehabilitation and Research Center for Deaf Children, emphasizes it is also important for young people and seniors to adopt a healthy lifestyle and take precautions to avoid hearing loss.

Listening to music using earphones in a noisy environment, which many young people do while commuting, is very unwise, Hu says.

Related: Lending an ear to children