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Fetal Care

Conditions and Abnormalities


Dr. Vlastos and Dr. Yang perform a twin-twin transfusion syndrome (TTTS) fetal surgery using minimally invasive instruments.

The caring, compassionate experts of the St. Louis Fetal Care Institute will be with you every step of the way, no matter what challenge you face.

We want to be sure that our patients understand exactly what is going on with their baby, so we make ourselves available for your questions. To help you better understand the conditions and abnormalities both you and your baby may experience, here is a listing and description of some of the fetal medical conditions that we diagnose and treat:

 Congenital Diaphragmatic Hernia (CDH): A condition in which the baby’s chest does not form correctly, allowing for internal organs such as the stomach, liver, kidney and small intestine to shift into the chest cavity. The displaced organs can prevent the lungs from developing properly and can also shift the location of a baby’s developing heart. Learn about treatment options.

 Congenital Cystic Adenomatoid Malformation (CCAM): A condition in which fluid-filled cysts form in the lung tissue of a fetus. Fetuses with CCAM are closely monitored and surgery is typically performed after birth to remove the mass in the lungs. In rare cases, intervention may be required before birth: The mass may need to be removed if it is affecting heart function or a catheter may need to be placed into one of the cysts to make the CCAM smaller.

 Twin-Twin Transfusion Syndrome (TTTS): Occurs when twin fetuses share the same placenta, and there is unequal sharing of blood flow between the fetuses.  One twin receives more blood than the other – a condition that is harmful to both the baby who doesn’t receive enough blood and the baby who receives too much. Learn about treatment options.

 Amniotic Band Syndrome (ABS): Refers to a condition in which the amniotic membrane has become injured and pieces of it have become attached to the fetus. These amniotic strands can form constrictive bands which wrap around body parts, like a rubber band.  The bands constrict blood flow and can cause permanent damage and even, amputation of limbs. Learn about treatment options.

 Twin Reversed Arterial Perfusion Sequence (TRAP): A rare birth condition in which a fetus born without a functioning heart takes the blood supply from its fully formed twin, known as a “pump” twin. The heart of the pump twin has to work harder to compensate for the blood that is being taken by the nonviable, acardiac twin. This overexertion of the developing heart puts the pump twin at risk for heart failure. Learn about treatment options.

 Sacrococcygeal Teratomas (SCT): This is the most common type of tumor found in newborns and is typically located between the coccyx and the sacrum, a bone at the end of the vertebral column. These tumors can actually becomes as large as the baby itself. When a tumor becomes severely enlarged, it can strain the baby's heart. This is an indication for either fetal surgery or early delivery. Learn about treatment options now. Learn about treatment options.

 Giant Neck Masses (GNM): These are tumors that can grow large enough to distort and obstruct the baby’s airway. For a baby with a significantly obstructed airway, open fetal surgery known as an EXIT procedure may be needed to clear the airway before the baby is born.

 Hypoplastic Left Heart Syndrome (HLHS): A congenital heart defect in which the left side of the heart does not develop properly. The left ventricle, which pumps to the body, and the aorta, responsible for carrying the blood, is too small. In hypoplastic left heart syndrome, the valves that regulate blood flow into the left ventricle and to the aorta are too narrow or closed.


A complete list of fetal abnormalities and conditions includes:


 Abdominal Wall Defects

  • Gastroschisis
  • Omphalocele

 CNS Lesions

  • Anencephaly
  • Hydrancephaly
  • Hydrocephalus
  • Myelomeningocele (Spina Bifida)
  • Holoprosencephaly
  • Encephalocele
  • Vein of Galen Aneurysm

 Urologic Problems

  • Bladder Outlet Obstruction (BOO)
  • Hydronephrosis
  • Dysplastic kidneys

 Congenital Heart Disease

  • Congenital Heart Block
  • Hypoplastic Left Heart Syndrome (HLHS)
  • Pulmonary Atresia with Intact Ventricular Septum

 Craniofacial Anomalies

  • Cleft Lip
  • Cleft Palate

 Intestinal Problems

  • Duodenal and Intestinal Atresia
  • Esophageal Atresia with Tracheoesophageal Fistula
  • Meconium Ileus
  • Imperforate Anus

 Limb Problems

  • Skeletal Dysplasia
  • Amniotic Band Syndrome (ABS)

 Airway Problems

  • Cystic hydgroma
  • Micrognathia
  • Congenital Airway Obstruction (CHAOS)
  • Giant Neck Masses

 Lung Problems

  • Congenital Diaphragmatic Hernia (CDH)
  • Congenital Cystic Adenomatoid Malformation (CCAM)
  • Pulmonary Sequestration
  • Fetal Chylothorax or Hydrothorax
  • Pulmonary Agenesis


  • Platelet Alloimmunization
  • Red Cell Alloimmunization
  • Non-immune Hydrops


  • Sacrococcygeal Teratoma (SCT)
  • Neuroblastoma

 Twin Abnormalities

  • Twin-Twin Transfusion Syndrome (TTTS)
  • Twin-Reversed Arterial Perfusion Sequence  (TRAP Sequence)
  • Discordant Intrauterine Growth Restriction (IUGR)
  • Discordant Structural Anomalies

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