ENT Head & Neck Surgery Center

Rm 02, 5/F., Kai Seng Commerical Centre,
4-6 Hankow Road, TST Kln, HK
(near Kowloon Hotel)
Tel: (852) 3100 0555
Fax: (852) 3100 0556

Lawrence Chow / ENT Doctor

Interesting Findings About Microtia That Pregnant Women May Want to Know

Pregnant women typically seesaw between being happy about their unborn babies and worrying about their babies’ health. Their concerns aren’t unfounded considering that congenital defects form within the womb, and these congenital defects can range from physical abnormalities to mental retardation.


Among these physical abnormalities are undeveloped external ears, a condition known as microtia. But it isn’t just the atypical size and shape of the earlobes that characterize microtia – it’s also characterized by hearing loss.


Are you intrigued by microtia yet? If you are, you will find these interesting findings about microtia in unborn babies and infants.


Its Cause Remains a Mystery

Scientists have yet to identify a specific cause of microtia. But there are a few theories including malfunctions in a gene located in chromosome 22.


The interplay of genetics and environment in the development of microtia in the womb is also not fully understood yet. In current medical literature, between 3 and 34 percent of patients with microtia have a genetic component.


Scientists, nonetheless, have confirmed that neurofibromatosis Type 2 (NF2), an autosomal dominant disorder, is a risk factor in microtia. If one parent has NF2, his or her children will have a 50-50 chance of getting microtia.


Yet another possible, but unconfirmed risk factor, is the use of isotretinoin, an anti-acne medication. Isotretinoin (Accutane) can result in a pattern of congenital defects believed to be a combination of genes and environmental factors.


It’s More Common in Some Areas

There are no generally accepted theories for why microtia has a higher incidence rate in Latin America, particularly Ecuador, and Asia than in other areas of the world. If you are in these areas, you may want to talk to your doctor about decreasing the risks of your unborn child getting congenital defects.


Boys also seem to be more affected by microtia than girls although both genders will experience similar signs and symptoms. The right ear also seems to be more affected than the left ear, but a small percentage of children with microtia will have it in both ears (i.e., bilateral microtia).


It Can Occur with Other Conditions

Microtia can also occur with other distinct medical conditions. The three more common conditions are:


  • Treacher Collins syndrome (TCS) is a genetic disorder characterized by physical abnormalities eyes, ears and cheekbones, as well as the chin.
  • Hemifacial microsomia (HFM) is a congenital disorder affecting the proper development of the ears, mouth and mandible.
  • Goldenhar syndrome causes physical defects in the face and head. It’s a rare congenital disease.


There are also maternal behaviors and conditions that can increase the risk of microtia in unborn babies. Women with diabetes before their pregnancy have been shown to have higher risk compared to women without diabetes. Pregnant women on a diet characterized by low levels of folic acid and carbohydrates also seem to have an increased risk for their babies developing microtia.


If you would like to learn more about microtia and its treatment, please consult HK ENT specialist.





HK ENT Specialist Ltd.

Hong Kong based ENT clinic centre

For ENT Services, Audiology & Speech Therapy,

Sleep Disordered Breathing Management,

Hearing Aid Prescription & Medical Cosmetic Services


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