Micrognathia

Micrognathia is when the lower jaw is smaller than normal. In some cases, this can cause problems with feeding, breathing and sleeping.

What is a Micrognathia?

Micrognathia is when the lower jaw (mandible) is smaller than normal. In some cases, this can cause problems with feeding, breathing and sleeping. This occurs in about 1 in every 1,500 births.

What Causes Micrognathia?

There are some cases where the cause of micrognathia is not known, but it is often related to genetic conditions, such as:

  • Achondrogenesis
  • Cleft lip
  • Cleft palate
  • Pierre Robin syndrome
  • Stickler syndrome (Hemifacial Microsomia)
  • Treacher Collins syndrome
  • Trisomy 13 or 18

Genetic conditions are abnormalities in genes that are passed down from a parent (inherited), or can happen on their own for no reason.

What are the Signs and Symptoms of Micrognathia?

Sometimes, signs of micrognathia can be seen on an ultrasound test during pregnancy. These include a smaller-than-normal lower jaw or chin. In extreme cases, the ultrasound may also show that there is too much amniotic fluid around the baby This is called polyhydramnios.

How is Micrognathia Diagnosed?

Micrognathia can sometimes be diagnosed in the womb based on the signs seen on ultrasound. It can also be diagnosed after delivery based on how your child’s jaw and chin look.

How is Micrognathia Treated?

Your doctor will watch your baby’s development by ultrasound throughout your pregnancy. After birth, your baby will be examined and may be referred to a craniofacial specialist.

In some cases, no treatment is needed. If the jaw corrects itself, it typically happens around 6 to 18 months of age. In mild cases, micrognathia can be treated by placing your baby on their stomach or side to sleep. If your baby has trouble eating, you can feed them in an upright position or use special nipples for bottle feeding. When the jaw corrects itself with growth, breathing and feeding problems usually go away.

In more severe cases, a tube may be inserted through the nose for feeding or to open up the airway. Surgery may be needed to help your child breathe more easily, to place their tongue in the correct spot or to lengthen the lower jaw. More surgeries may be needed as your child grows. 

Possible Problems

Babies with micrognathia may have trouble feeding. This can cause poor weight gain and failure to thrive. Follow up with your health care provider, regularly, to make sure your child is getting enough calories and is eating comfortably. Some children need special equipment or positioning to help them eat or breathe more easily.

Lifelong Considerations

Your baby will be monitored until the lower jaw corrects itself or until your they reach physical maturity. This is usually between 17 to 25 years of age. Surgery may be done to make the lower jaw larger or to make it easier to breathe. As your child ages, an orthodontist may be able to help move adult teeth into a normal position.

If your child’s micrognathia is not associated with a genetic condition that has long-term symptoms, and if your child is able to eat and breathe without trouble, they usually have little to no health problems in the future.