Reviewed By Medical Advisory Board
fetalis is a condition in the fetus
characterized by an abnormal collection of fluid with at least two of the
(fluid beneath the skin, more than 5 mm).
(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 :
Size greater than dates
Decreased fetal movement
Abnormal serum screening
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
cause 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
(High output failure from anemia, sacrococcygeal teratoma, fetal adrenal
- Impaired venous return
- Obstruction to normal lymphatic flow
- Increased capillary permeability
- Decreased colloidal osmotic pressure
Some conditions may involve more than one mechanism . For example,
parvovirus may cause cardiomyopathy and anemia from marrow suppression.
Conditions Associated with NIH
(This list is not exhaustive)
- 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, Pena-Shokeir,
- Fetal Anemia
- Alpha (α) thalassemia, parvovirus, fetal hemorrhage, G-6-PD deficiency
- Parvovirus, CMV, syphilis, coxsackie virus, rubella, toxoplasmosis, herpes,varicella, adenovirus,
enterovirus, influenza, listeria
- Thoracic Abnormalities
- Congenital cystic adenomatoid malformation (CCAM) , chylothorax, diaphragmatic hernia,
mediastinal tumor, skeletal dysplasias
- Twin to twin transfusion Severe anemia in the donor twin or high-output failure in the recipient
- Fetal sacrococcygeal teratoma, hemangiomas (Hepatic, Klippel-Trenaunay syndrome),
fetal adrenal neuroblastoma, placental tumors (chorioangioma)
- Cystic hygromas,
inheritable disorders of metabolism (lysosomal
storage diseases) ,maternal thyroid disease, congenital nephrotic syndrome.
- Obtain maternal history (including pedigree)
- Evaluate for immune hydrops
- Obtain maternal indirect Coombs test to screen for antibodies associated with blood
- Evaluate for nonimmune hydrops
- Level II sonogram with Doppler measurement of the peak systolic velocity
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
- 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
- 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
nonimmune hydrops test for :
- Storage disorders such as
Gaucherís, gangliosidosis, sialidosis, beta-glucuronidase deficiency, and
- Enzyme analysis and carrier testing in parents and/or analysis of
fetal or neonatal blood or urine.
- Histological examination of fetal tissues.
- Maternal thyroid antibodies
||Fetal blood sampling followed by
in utero transfusion
||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
The mother may develop edema , hypertension, and proteinuria during conservative management of hydrops
a condition known as
(also known as pseudotoxemia or Ballantyne syndrome) .
Symptoms may persist after delivery.
- Long term prognosis depends on underlying cause and severity of the heart
- If the cause of NIH cannot be determined, the perinatal mortality is
- Prognosis is much poorer if diagnosed at less than 24 weeks , pleural effusion
is present, or structural abnormalities are present .
Pulmonary hypoplasia is a common cause of death in neonates
with plerual effusions.
- Fetal hydrops associated with a structural heart defect is associated with
an almost 100% mortality rate.
- 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.
- Follow up of the fetus will depend on the gestational age of the fetus, and the mother's
wishes regarding intervention.
If treatment has been successful or hydrops is resolving spontaneously, the
fetus may be followed with repeat sonograms every 1 to 2 weeks and antenatal
- Patients treated for immune hydrops are usually delivered at 37 weeks' or when fetal lung maturity has been confirmed.
- Consultation with the neonatologist may help to decide when it is
appropriate to proceed with preterm delivery for possible postnatal treatment
- The mother should be evaluated frequently for signs of "mirror" syndrome.
The fetus should be delivered at tertiary care center with neonatologists and other
There is no evidence that delivery by cesarean section has a marked effect on
Cord blood should be obtained at delivery
A postmortem evaluation should be performed in all cases of
hydrops that result in neonatal death.
One study showed that a combined approach of a thorough antenatal assessment
and autopsy may be more likely to determine the cause of non-immune hydrops .
Wilkins, I. Nonimmune hydrops. In Creasy and Resnick's
Maternal Fetal- Medicine Principles and Practice sixth ed.Ed Creasy R et al. ,
Bianchi DW, Crombleholme TM, D'Alton ME.
Fetology: Diagnosis & Management of the Fetal Patient.1st ed McGraw-Hill
Professional 2000 pp 959-965
Rodriquez MM, Chaves F, Romaguera RL, Ferrer
PL, delaGuardia C, Bruce JH. Value of autopsy in nonimmune hydrops fetalis:
series of 51 stillborn fetuses. Pediatr Devel Path 2002;5:365-374.