In many cases, targeted sonographic and laboratory evaluation will identiy the underlying cause of fetal hydrops. hese include cases due to fetal anemia, arrhythmia, structural abnormality, aneuploidy, placental abnormality, or complications of monochorionic twinning. Depending on the circumstances, initial evaluation includes the following: 1.
2.
Targeted sonographic fetal and placental examination, including:
A detailed anatomical survey to assess for the structural abnormalities listed in Table 15-4
MCA Doppler peak systolic velocity to assess for fetal anemia
Fetal echocardiography with M-mode evaluation 3.
Amniocentesis for fetal karyotype and for parvovirus B19, cytomegalovirus, and toxoplasmosis testing as discussed in Chapter 64. Consideration of chromosomal microarray analysis if fetal anomalies are present 4.
Kleihauer-Betke test for fetomaternal hemorrhage if anemia is suspected, depending on findings and test results 5.
Consideration of testing for alpha-thalassemia and/or inborn errors of metabolism.
Isolated Efusion or Edema. Although one efusion or anasarca alone is not diagnostic for hydrops, the above evaluation should be considered if these are encountered, as hydrops may develop. For example, an isolated pericardial eusion may be the initial finding in fetal parvovirus B19 infection (Chap. 64, p. 1217). n isolated pleural efusion may represent a chylothorax, which is amenable to prenatal diagnosis, and for which fetal therapy may be lifesaving if hydrops develops (Chap. 16, p. 324). Isolated ascites also may be the initial inding in fetal parvovirus B 19 infection, or it may result from a gastrointestinal
TABLE 15-4. Categories and Etiologies of Nonimmune Hydrops Fetalis
Structural defects: Ebstein anomaly, Fallot tetralogy with absent pulmonary valve, hypoplastic left or right heart, premature closure of ductus arteriosus, arteriovenous malformation (vein of Galen aneurysm)
Bradycardia, as may occur in heterotaxy syndrome with endocardial cushion defect or with anti-RolLa antibodies
Cystic hygroma, systemic lymphangiectasis, pulmonary lymphangiectasis
Parvovirus B19, syphilis, cytomegalovirus, toxoplasmosis, rubella, enterovirus, varicella, herpes simplex, coxsackievirus, listeriosis, leptospirosis, Chagas disease, Lyme disease
Skeletal dysplasia with very small thorax
Meconium peritonitis, gastrointestinal tract obstruction
Congenital (Finnish) nephrosis, Bartter syndrome, mesoblastic nephroma
Placental, Twin, and Cord Abnormalities 5
Placental chorioangioma, twin-twin transfusion syndrome, twin reversed arterial perfusion sequence, twin anemia polycythemia sequence, cord vessel thrombosis
Inborn errors of metabolism: Gaucher disease, galactosialidosis, GM1 gangliosidosis, sialidosis, mucopolysaccharidoses, mucolipidoses
Tumors: sacrococcygeal teratoma, hemangioendothelioma with Kassabach-Merritt syndrome apercentages reflect the proportion within each category from a systematic review of 6775 pregnancies with nonimmune hydrops.
Modified from Bellini, 2015.