An Overview of Hydrops Fetalis

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Hydrops fetalis, also known as hydrops, is a rare condition that is a marker for other fetal complications. It is a serious and potentially life-threatening condition involving severe swelling in a fetus or newborn, and an abnormal amount of fluid in at least two fetal organs. In some cases, once an underlying cause is found, it can be treated. In cases where this condition can't be treated, the healthcare team will do everything they can to relieve symptoms and provide comfort.

Illustration of hydrops fetalis symptoms
Verywell / Gary Ferster


There are two kinds of hydrops fetalis: immune and nonimmune.

  • Immune: The immune type occurs when the immune system of the mother causes red blood cells in the fetus to break down. This is uncommon because of the Rh immunoglobulin treatment used with pregnant women who are Rh negative.
  • Nonimmune: The nonimmune type accounts for most cases of hydrops fetalis and is caused when diseases or other complications cause the fetus to have fluid management issues. Some of these complications can include severe anemias, congenital infections, defects in the heart or lungs, chromosomal abnormalities, and liver disease.


The symptoms of hydrops are seen on ultrasound examination and can include the abnormal gathering of fluid in various organ spaces, including:

  • Around the heart or lungs
  • Generalized edema
  • The abdominal cavity

Other signs of hydrops can include excess amniotic fluid and placental thickening.

One symptom by itself does not necessarily mean your baby has hydrops fetalis, but it warrants further examination.


Diagnosing hydrops prenatally is done with ultrasound and requires the presence of abnormal fluid in at least two fetal body areas. The condition is diagnosed prenatally in over 90% of cases. In order to determine the type of hydrops, the mother's blood will be tested. Fetal blood sampling or amniocentesis may also be done.

Once a diagnosis of hydrops fetalis is made, other tests will be done to determine the underlying cause of the hydrops, so it can be treated appropriately. These tests can include a fetal echocardiogram, testing for infections or congenital issues, and genetic tests.

A genetic counselor or high-risk maternal-fetal medicine specialist might become part of your pregnancy care team to ensure that you and your baby are getting the level of care that you need.


Treatment options for hydrops fetalis depends on the underlying cause. However, it's important to note that this condition has a high mortality rate.

If there is no available treatment for the cause or if no cause is found, comfort measures are taken to relieve symptoms and provide care.

Low blood count complications can be potentially treated by fetal blood transfusion via PUBS (percutaneous umbilical blood sampling). This involves amniocentesis-guided blood sampling via the umbilical cord, and new blood products can be delivered the same way. For non-immune hydrops, treatment is based on the cause of the hydrops.

The mortality rate for non-immune hydrops fetalis is between 60% and 90%, depending on the underlying cause. The earlier in the pregnancy hydrops is found, the more serious it is. Once a cause is found, if treatment is available, the risks and benefits will be discussed with you.

When the Baby Is Born

In some cases, a Cesarean birth will be recommended for the delivery of the baby. Once the baby is born, they may need a variety of services, including aggressive resuscitation, breathing tube placement, chest tubes, and IV lines for a variety of things.

Treatment is often serious and very aggressive, and babies with hydrops can be very sick at birth. Talk with your doctor about the level of care your baby will likely need, how you can still be a part of the early care of your baby, and the NICU services offered.


If not treated in time, hydrops fetalis can become fatal for your baby very quickly. This condition is serious, and once diagnosed, urgent treatment is necessary to avoid fetal death. Some complications of hydrops in pregnancy and in infants include:

  • Fluid around the heart and lungs, affecting breathing and heart function
  • Increased risk of preterm labor and birth due to the excess amniotic fluid
  • Severe breathing problems or respiratory distress
  • Severe low blood sugar, which puts infants at risk for seizures and possible brain injury
  • Underdeveloped lungs because of lack of space in the chest from swollen organs or excess fluid

Risks can vary depending on the underlying cause of the hydrops and where the fluid has collected. Talk with your treatment team about the possible complications or risks for your specific situation. Your team will do their best to reduce risk of complications and help you manage any that do arise.

A Word From Verywell

Complications of a pregnancy can be stressful and scary, and hydrops fetalis is a serious condition. However, many of the underlying causes of hydrops are treatable. Talk with your treatment team about the causes of the hydrops, what your treatment options are, and the risks and benefits of all of the options. Your team will be able to take into consideration your specific circumstances and the health of your baby to help you make the decision that is best for your family.

3 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institutes of Health. Hydrops fetalis.

  2. Moreno CA, Kanazawa T, Barini R, Nomura ML, Andrade KC, Gomes CP, Heinrich JK, Giugliani R, Burin M, Cavalcanti DP. Non-immune hydrops fetalis: A prospective study of 53 cases. Am J Med Genet A. 2013;161A(12):3078-86. doi:10.1002/ajmg.a.36171

  3. Meng D, Li Q, Hu X, et al. Etiology and outcome of non-immune hydrops fetalis in southern China: report of 1004 casesSci Rep. 2019;9(1):10726. doi:10.1038/s41598-019-47050-6

By Jaime R. Herndon, MS, MPH
Jaime Rochelle Herndon, MS, MPH, MFA, is a former writer for Verywell Family covering fertility, pregnancy, birth, and parenting.