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Hydrops Fetalis

Hydrops fetalis is a condition in the fetus characterized by an abnormal collection of fluid with at least  two of the following:

  • Edema
    (fluid beneath the skin, more than 5 mm).
  • Ascites
    (fluid in abdomen)
  • Pleural effusion
     (fluid in the pleural cavity, the fluid-filled space that surrounds the lungs)
  • Pericardial effusion
    (fluid in the pericardial sac, covering  that surrounds the heart)

In addition, hydrops fetalis is frequently associated with polyhydramnios and a thickened placenta (>6 cm).


Hydrops fetalis is typically diagnosed during ultrasound evaluation for other  complaints such as :

  • Polyhydramnios
  • Size greater than dates
  • Fetal tachycardia
  • Decreased fetal movement
  • Abnormal serum screening
  • Antenatal hemorrhage


Hydrops fetalis is found in about 1 per 2,000 births, and is categorized as immune or nonimmune hydrops.

Immune hydrops (accounts for 10-20%of cases)
  • Maternal antibodies against red-cells of the fetus cross the placenta and coat fetal red cells which are then destroyed (hemolysis) in the fetal spleen.
  • The severe anemia leads to
    • High-output congestive heart failure.
    • Increased red blood cell production by the spleen and liver leads to hepatic circulatory obstruction (portal hypertension)
  • Anti-D, anti-E, and antibodies directed against  other Rh antigens comprise the majority of antibodies responsible for hemolytic disease of the newborn .
    • However, there are numerous, less commonly encountered, antibodies such as anti-K (Kell), anti-Fya (Duffy) , and anti-Jka (Kidd)  that may also causes of hemolytic disease of the newborn.

Nonimmune hydrops (accounts for 80 -90% of cases)

  • Any other cause besides immune.
  • In general nonimmune hydrops (NIH) is caused by a failure of the interstitial fluid (the liquid between the cells of the body) to return into the venous system .

This may due to:

  • Cardiac failure
  • Impaired venous return
  • Obstruction to normal lymphatic flow
  • Increased capillary permeability
  • Decreased colloidal osmotic pressure


Normal return of of interstitial fluid to veins though lymphatic system
(high pressure to low pressure)
Lymph  capillaries
and veins
Mechanisms that may cause increased interstitial fluid
Increased capillary permeability

OR decreased colloidal osmotic pressure

obstruction to lymph flow Cardiac failure


Impaired venous return


  • Conditions Associated with NIH
    (This list is not exhaustive)

    • Cardiac
      • Cardiomyopathy, Ebstein's anomaly, pulmonary atresia, coarctation of the aorta, hypoplastic left heart, complete AV canal, left sided obstructive lesions, premature closure of the foramen ovale
      • Intracardiac tumors (tuberous sclerosis)
      • Cardiac arrhythmia
        • SVT, flutter, heart block, WPW syndrome
    • Chromosomal /Genetic Syndromes

      • T13, T18, T21, XO (Turners syndrome) ,Noonan syndrome , multiple pterygium syndrome
    • Fetal Anemia
      • Alpha (α) thalassemia, parvovirus, fetal hemorrhage, G-6-PD deficiency
    • Infection
      • Parvovirus, CMV, syphilis, coxsackie virus, rubella, toxoplasmosis, herpes,varicella, adenovirus, listeria
    • Thoracic Abnormalities
      • Congenital cystic adenomatoid malformation (CCAM) , chylothorax, diaphragmatic hernia, skeletal dysplasias
    • Twinnning
      • Twin to twin transfusion Severe anemia in the donor twin or high-output failure in the recipient
    • Miscellaneous
      • Fetal sacrococcygeal teratoma, hemangiomas (Hepatic, Klippel-Trenaunay syndrome), placental tumors (chorioangioma) , cystic hygromas, inheritable disorders of metabolism (lysosomal storage diseases) ,maternal thyroid disease


  • Obtain maternal history (including pedigree)
  • Evaluate for immune hydrops
    • Obtain maternal indirect Coombs test to screen for antibodies associated with blood group incompatibility.
  • Evaluate for nonimmune hydrops
    • Level II sonogram with Doppler measurement of the peak systolic velocity (PSV)  in the fetal middle cerebral artery (MCA) to assess for fetal anemia. If there is evidence for anemia or equivocal result obtain:
      • Maternal blood counts and hemoglobin electrophoresis (with hemoglobin DNA analysis), Kleihauer-Betke stain, glucose 6-phosphate dehydrohgenase deficiency screen.
      • Maternal TORCH titers, RPR, listeria, parvovirus B19, coxsackie, adenovirus, and varicella IgG and IgM, as indicated.
    • Fetal echocardiogram
      • Consider fetal heart rate monitoring for 12 to 24 hours if fetal arrhythmia is suspected.
    • Amniocentesis for fetal karyotype and PCR (polymerase chain reaction) for infections OR fetal percutaneous blood sampling for same and in addition fetal liver function; and metabolic testing if indicated.
    • In the presence of a family history of an inheritable metabolic disorder or recurrent nonimmune hydrops test for :
      • Storage disorders such as Gaucherís, gangliosidosis, sialidosis, beta-glucuronidase deficiency, and mucopolysaccharidosis,
      • Maternal thyroid antibodies


Cause Treatment
Fetal anemia Fetal blood sampling followed by in utero transfusion
Fetal Arrhythmia Medications such as digoxin, sotalol, propanolol , flecainide, amiodarone
Intrinsic thoracic malformations Thoracentesis or thoracoamniotic shunt for pleural effusions in select cases
Twin to twin transfusion Fetoscopic laser ablation of communicating vessels
Syphilis Penicillin



  • Long term prognosis depends on underlying cause and severity of the heart failure.
  • If the cause of NIH cannot be determined, the perinatal mortality is approximately 50%
  • Prognosis is much poorer if diagnosed at less than 24 weeks , pleural effusion is present,  or structural abnormalities are present .
  • If early in pregnancy (less than 24 weeks)  with no treatable cause the option of termination may be a consideration.
  • Recurrence is uncommon unless related to blood group incompatibility (isoimmunization) or inheritable disorder.

Maternal complications
 Mirror syndrome (also known as  pseudotoxemia or Ballantyne syndrome) may develop during conservative management of hydrops

  • Edema
  • And may also have HTN and proteinuria



    Repeat sonogram periodically to further evaluate fetal anatomy and progression of disease.
    Antenatal testing as indicated after fetal viability.



    Unless there is evidence dleiver at 34 weeks untless hydrops is resolvoing or tretament has been efective

    Manage until 37 weeks or until fetal lung maturity has been confirmed.

    Plan for delivery at tertiary care center with neonatologists and other appropriate specialists.
    Most of the time fetuses are delivered with elective cesarean section. However, there is no evidence that mode of delivery has a marked effect on outcome.
    Pediatric team should be aware about the nature of fetal problem before delivery as resuscitation is often difficult and adequate senior assistance must be available.

    Co-ordinated delivery room resuscitation
    Vigorous cardiorespiratory stabilization
    PPHN common, therefore aggressive ventilatory management often necessary including HFOV and NO
    thoracentesis, paracentesis and fluid replacement as needed
    inotropic support as indicated
    cautious diuretic administration
    factors to consider in resuscitation:
    airway edema
    chest wall edema
    pulmonary edema/pleural effusions/pulmonary hypoplasia/RDS
    perinatal depressions/hypoxia/acidosis
    Supportive care (especially if born prematurely)
    Specific therapy based on underlying etiology





    Postmortem examination in all cases of NIFH that result in neonatal death.
    An accurate diagnosis may not always be possible, and this limitation must be clearly explained to parents of affected fetuses who opt for another pregnancy.
    A combined approach of a thorough antenatal assessment and autopsy when indicated was able to determine the cause of non-immune hydrops in over 90% of cases in one study.

    Cord blood at delivery - irrespective of outcome .

    1 . Blood Group Serology and tying
    2 . Chromosome analysis.
    3 . Total protein and albumin
    4 . TORCH titre
    5 . Hb and Hb - EPP . ( H.P.L.C. )
    6 . Vacuolated lymphocytes
    7 . Enzymology ( red cell and lysosomal enzyme ).



    Wilkins, Isabelle. Nonimmune hydrops. In Creasy and Resnick's Maternal Fetal- Medicine Principles and Practice sixth ed.Ed Creasy R et al. , 2009, Saunders. pp505-517



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