One in 28 babies is born with a structural birth defect. Advances in prenatal diagnosis have provided a window into the womb to accurately elucidate the precise details of anatomic defects and assess their impact on development (Table 42-1). These allow new possibilities for targeted innovation in prenatal therapy. Further, fetal therapy offers the ability to alter the natural history of some fetal disorders, converting a previously lethal diagnosis to a nonlethal diagnosis. In some cases, the progress of a disorder can be halted prior to irreversible damage. The scope for fetal therapy includes both medical interventions and surgical interventions, fetoscopic and open.
TABLE 42-1DEFECTS AFFECTING THE FETUS AND THEIR SEQUELAE |Favorite Table|Download (.pdf) TABLE 42-1DEFECTS AFFECTING THE FETUS AND THEIR SEQUELAE
|Anatomic Defect ||Effect on Development |
|Cystic adenomatoid malformation (CCAM) || |
|Sacrococcygeal teratoma (SCT) ||High output failure |
|Laryngeal atresia || |
Congenital high airway obstruction syndrome (CHAOS)
|Twin-twin transfusion syndrome (TTTS) and twin-reversed arterial perfusion (TRAP) syndrome || |
|Myelomeningocele (MMC) || |
|Urethral obstruction || |
|Congenital diaphragmatic hernia (CDH) ||Pulmonary hypoplasia |
|Aortic stenosis ||Hypoplastic left heart syndrome |
Embarking on fetal interventions requires a dedicated multidisciplinary team. The team should be comprised of a specialized group of individuals with expertise in fetal disease. At a minimum, the team should include maternal fetal medicine specialists, obstetricians, radiologists, pediatric surgeons, cardiologists, ultrasonographers, anesthesiologists, nurses, geneticists, neonatologists, social workers, and other pediatric subspecialists as needed. State-of-the art fetal imaging techniques such as high resolution 3-dimensional (D) and 4-D ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and echocardiography are paramount to the success of the fetal enterprise for accurate fetal diagnosis and detailed anatomy. Recent advances in techniques such as 3-D printing are increasingly used in treatment planning. In addition, advances in molecular diagnosis allows for the diagnosis of many genetic diseases in utero.
Deciding whether a mother and fetus are candidates for fetal therapy is very complex. Maternal factors such as overall health, cervical length, uterine abnormalities, and placental positioning are all determinants of candidacy. Fetal considerations for candidacy for fetal therapy include evaluation for genetic disorders or other associated congenital anomalies. Gestational age and severity at diagnosis are other key factors as the success of many of these interventions are dependent on being done in a time-sensitive critical window. In addition, in some cases, delivery of the fetus early for postnatal therapy rather than fetal therapy may be indicated.
In the past, fetal intervention was limited to conditions in singleton pregnancies in which the life of the fetus was threatened. In recent years, the indications for fetal intervention have been extended to non–life-threatening but potentially devastating conditions, such as myelomeningocele, and to multiple gestations for twin-twin transfusion syndrome (TTTS).
The evolution of fetal intervention holds tremendous promise for altering the ...