Fetal Care
Congenital Pulmonary Airway Malformation

What is Congenital Pulmonary Airway Malformation?

A congenital pulmonary airway malformation (CPAM) is a mass of abnormal fetal lung tissue that forms during pregnancy. This mass, or lesion, is usually located in one lung and it does not function as normal lung tissue.

Lesions vary in size and appearance and can change significantly during the pregnancy. A baby with CPAM can have one lesion or many. These lesions can be solid or filled with fluid.  

There is no known cause for CPAM, which was previously referred to as congenital cystic adenomatoid malformation (CCAM). The condition is relatively rare, affecting about 1 in 25,000 pregnancies. It is slightly more common in males than in females. CPAM is not hereditary, so it usually does not recur in families. 

Comprehensive, Expert Care for CPAM  

At the Cincinnati Children's Fetal Care Center, our experienced maternal and fetal care specialists offer a complete range of diagnostic tests and treatment options for babies with CPAM. 

Our team has evaluated more than 400 babies with CPAM since 2004. We know that a diagnosis of CPAM is an emotional experience for families, and in some cases difficult decisions about treatment must be made quickly. At the Fetal Care Center, we are here to help, providing a thorough, compassionate approach to each patient’s care.

For most babies with a congenital pulmonary airway malformation, the condition is not life threatening. Sometimes, the lesions decrease in size or can no longer be seen during the pregnancy. Other times, the lungs develop normally despite the presence of these lesions.  

In about 10 percent of cases, CPAM can cause serious problems for the baby and sometimes, for the mother as well. The most serious problems occur when babies develop hydrops, a prenatal form of heart failure characterized by fluid build-up in the skin, chest or abdomen. Babies who have CPAM and hydrops typically will not survive unless they can respond quickly to medicine or undergo fetal surgery to remove the lesions.  

Hydrops can cause “mirror syndrome,” in which the mother “mirrors” the baby’s illness. The mother can develop high blood pressure and fluid retention. This condition calls for immediate delivery of the baby since it puts the mother’s life at risk.

Congenital pulmonary airway malformation is often detected during a routine ultrasound during pregnancy. Additional tests can confirm the diagnosis, evaluate how severe the CPAM is, and identify any other problems. These tests include: 

  • Magnetic resonance imaging to determine the size and location of the CPAM and see how the lesions are affecting lung development
  • Fetal echocardiogram to assess whether the lesions are affecting the baby’s heart structure and function 

After the initial diagnosis, our team must monitor the baby’s and mother’s conditions closely throughout the pregnancy. The patient meets regularly with members of our team, who include a maternal-fetal medicine specialist, a surgeon and a nurse coordinator. Their goal is to explain all test results thoroughly and work with the patient to establish a comprehensive treatment plan. (After the initial diagnosis and meeting with the team, our team works closely with referring providers to carefully monitor the baby’s and mother’s condition throughout pregnancy. If preferred, our team can continue to monitor the mother’s and baby’s well-being and can update the referring provider.) 

Weekly ultrasound tests are very helpful because they can show whether the lesions are growing and whether hydrops is developing. Our team also uses ultrasound to calculate the CPAM volume ratio (CVR), which is a reliable indicator of the baby’s prognosis. CVR is the ratio of lesion volume to the baby’s head circumference. A CVR of less than 1.6 indicates a favorable prognosis; 1.6 or greater indicates an increased risk of hydrops and the possibility of fetal surgery. 

Another indicator of serious problems is swelling in the placenta. Placental swelling is associated with hydrops and is a sign of “mirror syndrome,” which means that the mother’s life could be at risk. In this case, our team will meet with the patient to discuss the option of immediate delivery. 

In most cases, the growth of the lesion stops at about the 26th week of pregnancy. Babies who reach this important milestone and have not developed hydrops are no longer at risk for this dangerous condition.

Many factors influence decisions about which fetal therapy to pursue for a baby with CPAM, if any. These include the size and number of lesions, whether the lesions are solid or filled with fluid, and whether hydrops or mirror syndrome has developed. 

Steroid Treatment

When the lesions are solid or are growing too quickly, our team may recommend steroid treatment as a first step. Steroids can slow the growth of the lesions, possibly allowing patients to avoid fetal surgery.  


When large, fluid-filled cysts are present, the medical team may recommend draining them using thoracentesis. This involves inserting a needle through the womb into the lesion and draining the fluid. To prevent future fluid build-up, the surgeon may place a thoracoamniotic shunt, or catheter, to continue draining fluid from the lesion into the amniotic cavity. 

Fetal Surgery 

If large, solid lesions are present and severe hydrops has developed, the team may recommend open fetal surgery to remove the lesions. Following surgery, ultrasound examinations are performed to monitor the baby’s condition. These babies are usually delivered by Cesarean section, if fetal surgery was required, and their prognosis is excellent after surviving fetal surgery − very few need breathing assistance after delivery. 

Early Delivery 

If mirror syndrome has occurred, our team will recommend early delivery to protect the life of the mother. Otherwise, we try to avoid early delivery as a more mature baby will tolerate  newborn care with greater ease and fewer complications.

Babies born with congenital pulmonary airway malformation are at high risk for complications during and after delivery. Complications can include breathing issues, underdeveloped lungs and high blood pressure, among others. Managing these problems is the first and most important step in caring for babies with CPAM after birth. Therefore, all babies with CPAM should be delivered at a center with a neonatal intensive care unit and pediatric surgical services. 

Lesions should be removed surgically since they can become infected or, in rare cases, become cancerous. The timing of surgery depends on the baby's symptoms after birth. If the baby has no breathing problems, he or she may be discharged home and scheduled for surgery sometime within the first year of life. 

In some cases, the lesions are very large and interfere with normal breathing, so surgery must take place immediately after birth. Our team may recommend a special birth plan which includes ex-utero intrapartum treatment (EXIT). This involves delivering the baby by Cesarean and immediately performing surgery while the baby is still connected to the placenta. Cincinnati Children's Fetal Care Center is one of only a few institutions in the United States offering EXIT as a management strategy for babies with severe CPAM. 

Even if immediate surgery is not necessary, some babies with CPAM will experience breathing problems at birth. They may need to be placed on a ventilator or have extracorporeal membrane oxygenation (ECMO), a type of heart-lung bypass machine.

The majority of babies with CPAM do well after the lesion is removed. In rare situations, patients who had large lesions may have small lungs and subsequent chronic lung disease. 

Specialists at Cincinnati Children’s have extensive experience in caring for children who were treated for CPAM. They provide long-term follow-up programs focused to help children reach their full potential.

Since 2004, physicians at the Fetal Care Center have evaluated more than 400 patients for congenital pulmonary airway malformation. Our team offers a comprehensive, interdisciplinary strategy for diagnosing and treating this condition.

  • Consistency. The same team of physicians cares for patients from diagnosis to delivery.
  • Collaboration. Physicians from many medical specialties share their expertise to ensure that each aspect of a child’s care is addressed.
  • Sophisticated treatment options. Our experience with CPAM means that we can provide the most effective therapies available.
  • Family-centered care. We encourage parents to participate in every aspect of their child’s care, and we value their input.

The Cincinnati Children's Fetal Care Center team works closely with referring obstetricians and maternal-fetal medicine specialists to facilitate prenatal management, and with pediatricians who will provide primary care once the baby has been discharged home.

Volume & Outcomes

The Cincinnati Children's Fetal Care Center has performed 418 evaluations for CPAM since 2004. Fetal patients diagnosed with low risk CPAM and treated at our Center have a 100% survival rate.

Fetal Therapy for CCAM / CPAM*
Open Fetal Surgery 7



Shunt Placement


*Data based on patients cared for at the Cincinnati Children's Fetal Care Center Feb. 1, 2004, through June 30, 2023.

For More Information

For more information or to request an appointment, contact the Cincinnati Children's Fetal Care Center at 1-888-338-2559 or use our online form.

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