Health Library

Hydrops Fetalis

What Causes Hydrops Fetalis?

The most common causes of non-immune hydrops are genetic or chromosomal abnormalities, congenital heart disease or arrhythmias, and fetal infections. Hydrops can also be caused by hematologic abnormalities that cause anemia, tumors or malformations in the thoracic, GI, lymphatic or urologic systems. In about 15% of cases, an underlying cause is not found.

What are the Symptoms of Hydrops Fetalis?

Before the baby is born, in addition to fluid buildup in the fetus, hydrops can be connected  with increased amniotic fluid volume (polyhydramnios) and a thickened placenta.

Symptoms when the baby is born can include swelling that can be severe, difficulty breathing, pale skin and an enlarged liver and spleen.

How is Hydrops Fetalis Diagnosed?

Hydrops is diagnosed on ultrasound when increased fluid is found in two of the baby’s body cavities. When there is concern for hydrops, more testing is done to find the underlying cause. This may include:

• Detailed fetal ultrasound and / or fetal MRI.
• Fetal echocardiogram to look for cardiac abnormalities.
• MCA doppler: this is an ultrasound assessment of the middle cerebral artery in the brain to screen for fetal anemia.
• Blood tests for infection.
• Fetal karyotype and other genetic testing. This can be done with amniotic fluid from a procedure called an amniocentesis.

How is Hydrop Fetalis Treated?

In some cases, therapies can be done before the baby is born to address specific things. These may include:

• Needle drainage of pleural effusions and / or ascites
• Thoracoamniotic shunt (a shunt between the chest wall and the amniotic fluid) for continued drainage of fluid around the lung
• Intrauterine blood transfusion in cases of fetal anemia
• Antiarrhythmic medications in cases of cardiac arrhythmias
• Fetoscopic laser ablation for twin-twin transfusion syndrome (TTTS)

After the baby is born, treatment focuses on managing fluid collections and finding underlying causes.

This often requires removing fluid from the lungs, abdomen or around the heart with a needle or chest tube immediately or soon after delivery. Many infants will need a breathing tube and mechanical ventilation to support their breathing. In cases where fetal anemia is contributing to hydrops, a blood transfusion may be given.

Hydrop Fetalis Prognosis

Overall survival for infants with hydrops is about 50%. Prognosis depends on the severity of the hydrops, the underlying condition and the gestational age at diagnosis and delivery. Prognosis is generally worse the earlier in pregnancy the hydrops is detected. These infants often have prolonged, complex neonatal intensive care unit (NICU) admissions.