Micrognathia is a smaller than normal jaw, often the lower jaw or chin. Micrognathia may be part of a syndrome, which is a condition where more than one body system is involved. A syndrome may be inherited (passed down from the parents) or come about spontaneously.

Pierre Robin (Pee-air Ro-ban) sequence refers to a combination of small jaw, a normal tongue that is crowded at the back of the throat and difficulty with breathing. Sometimes there is a wide cleft palate (hole in the roof of the mouth). It is not clear why this occurs, but it may happen because of some problem with development early in pregnancy. 

There are several reasons why the jawbone may not develop normally:

• Positional deformation (the chin is pressed against the chest of the baby)
• Intrinsic hypoplasia (restricted growth)
• Neurologic or neuromuscular problems (reduced movement related to muscle or nerve involvement)
• Connective tissue disorder (reduced movement related to connective tissue problems of the jaw)

The most important issue is that the airway may be blocked. Sometimes it is difficult to appreciate it in the early days after birth, and the struggle with breathing becomes more apparent a few days or weeks later. These babies often have difficulty gaining weight because they are using so much energy just to breath.

There are mild cases and severe cases. In mild cases, the airway may be improved by placing the baby on their stomach, and having gravity move the tongue a little forward. Even a small amount often helps. In more severe cases, a number of tests can be employed to help understand the severity of the problem, and make sure there are no other issues in the airway. Ultimately, some children may require surgery, including tongue-lip adhesion, mandibular distraction or tracheostomy. In every case, the child requires intensive care until the full extent of the problem is understood.

Pierre Robin occurs in about one per 8,500 live births. It occurs equally in males and females. We usually can not know the cause of Pierre Robin sequence, but we do know it is not caused by anything the mother did or did not do during pregnancy.

Doctors may see a small chin on a profile view of the face during a routine ultrasound. If your doctor suspects this, they will pay particular attention to the growth of the chin throughout the remainder of the pregnancy. 

When a smaller chin is noted, because of the increased likelihood of other birth defects, your doctor likely will refer you to a maternal-fetal medicine specialist (a doctor who is specially trained to manage high-risk pregnancies). This doctor will perform a more detailed ultrasound to look closely at your baby for other birth defects. Some doctors also may want to do an MRI at some time during the pregnancy to examine your baby’s palate.

If your doctor suspects a problem with your baby,  they will likely refer you to a maternal-fetal medicine specialist. The maternal-fetal medicine specialist may recommend additional tests:

Targeted ultrasound: The doctor will perform a targeted ultrasound to evaluate your baby for any other problems, paying special attention to the heart and skeleton. 

Amniocentesis: When micrognathia is suspected before your baby is born, we may recommended evaluation of the chromosomes. This is done with a genetic test called an amniocentesis. The doctor will discuss risks and benefits of this test with you before it is done. 

Fetal echocardiogram: Because of an increased risk of heart disorders seen with micrognathia, your doctor may recommend a fetal echocardiogram. The echocardiogram is an ultrasound that looks at the heart's anatomy, blood flow and circulation. A pediatric cardiologist would perform this test before your baby is born and maybe again after birth to confirm what they suspect initially on prenatal views.

Your team may recommend different positions to help your baby’s breathing. These positions, such as sleeping on the stomach, will be tried under safe monitoring. Another way to keep the airway open is with a special device placed in your baby's mouth on top of the tongue to hold it in place and keep it from blocking the airway while they sleep.

Also, your baby can be evaluated to see if one of three procedures may be needed:

• Tongue-lip adhesion
• Mandibular distraction
• Tracheostomy (if the first two procedures don't work)

Tongue-lip adhesion involves sewing the tongue to the lower jaw to make it more difficult to block the airway, especially the nasal passage.

Mandibular distraction can help the lower jawbone to grow. This is a surgical procedure in which a special appliance is inserted to literally stretch the jawbone over a number of days to weeks. A metal device is placed into the bone and extensions on the outside allow for daily stretching of the bone and soft tissue. The part of the device that extends out to the skin has a piece that may be turned with a key. This will allow the piece of the device in the bone to stretch the bone and tissue in the jaw. By using this device, no bone grafts are needed and doctors may be able to avoid a tracheostomy.

If a distraction device is used, care of the site will be reviewed with you as well as signs and symptoms of complications and device malfunction. The site needs to be kept clean and dry for healing and to prevent infection. 

A tracheostomy is a surgical procedure that places a hollow tube into the windpipe to create an airway. The tube is placed in the lower middle portion of the neck. The baby will breathe through this tube.

After a tracheostomy, babies will have more secretions because of the surgery and the tube that is in the airway. Frequent suctioning may be necessary. 

Oxygen can be provided through the new tracheotomy tube. The air should be humidified to keep the secretions loose. If the mucous is too thick, it can form a plug that may block the tube. This is life threatening. The tube is left in place for five to seven days to allow for healing. Then, the tube will be changed and can be switched to a metal tube with an inner cannula. This inner cannula can be removed and cleaned periodically, which helps keep the tube clear of secretions and maintain the airway. The surgical opening needs to be kept as clean and dry as possible to ensure that the site does not become infected. If the plan is for your baby to go home with a tracheostomy, the home care teaching will begin right away. You also will need to begin to prepare your home with the equipment necessary to care for your baby. Before your baby goes home, you will learn about all equipment, emergency procedures and daily care. 

Feeding is the second major issue with these babies. The cleft palate, in combination with the small tongue, prevents a baby from developing effective suction. This makes it hard for them to take in enough calories to grow. It also means breastfeeding may be unsuccessful. Breast milk or formula can be placed in a bottle to be given to the baby. It is a matter of trial and error to find out which nipple, hole size in the nipple and feeding position works best for your baby. 

When feeding, positioning the baby sitting and tipped slightly forward can help keep the tongue out of the way. However, it is sometimes very difficult to keep the tongue down to get the bottle nipple in the mouth. Sometimes, a feeding tube placed into the stomach is needed to ensure that the baby gets enough food. The placement of this gastrostomy tube is done in surgery. The tube is placed directly into the stomach through a small hole made in the abdomen. 

If a gastrostomy tube is necessary, the surgical site must be kept clean and dry to help healing and to prevent infection. Before we begin feedings through the tube, we give the gastrointestinal tract time to recover from surgery. We will teach you how to care for the tube and insertion site (also called a stoma) and how to feed your baby through this tube before they go home. 

Your baby will go home when they are able to keep their airway open and eat enough to grow and gain weight. It’s hard to predict the length of stay for these babies because of the wide variation in the type of interventions that may be needed. 

Many babies with this condition will go home with a variety of equipment, including an apnea monitor. As the parent, part of the discharge planning involves learning all you need to know to care for your baby at home. 

If your baby needs surgery, they will need time to recover and learn to eat enough to grow. Expect a minimum of 1 to 2 weeks for those minimally affected and 4 to 6 weeks for those who require a gastrostomy tube and/or tracheostomy. The length of stay can also be affected by associated anomalies.