Hydrops fetalis is a serious condition where abnormal amounts of fluid gather in two or more fetal compartments. This leads to ascites (fluid in the abdomen), pericardial effusion (fluid around the heart), pleural effusion (fluid around the lungs), and skin edema (fluid underneath the skin). There can also be an edematous (swollen) placenta, and polyhydramnios (greater than usual amount of amniotic fluid).
There are two types of hydrops fetalis. One type is nonimmune hydrops fetalis and the other is immune hydrops fetalis. Immune hydrops fetalis is a result of the mother’s immune system attacking the fetal red blood cells due to Rh incompatibility. This can occur when the mother is Rh negative and the fetus is Rh positive. The mother’s immune system will cause a break down of the fetal red blood cells causing anemia due to maternal antibodies cross the placenta. Fluid then accumulates in the fetus to compensate for this abnormality. This type of hydrops fetalis is unusual in this day and age due to Rhogam. You may remember your provider giving you Rhogam at 26-28 wks gestation. This was to prevent Rh sensitization. The second type of hydrops fetalis is nonimmune and is associated with different diseases like genetic abnormalities, infections, liver and heart disease among others. Nonimmune hydrops fetalis accounts for 85% of all cases.
As mentioned previously, hydrops fetalis is a life threatening condition regardless of whether the origin is immune or nonimmune. About half of the infants born with this condition will not survive. Survival depends, in large part, on the reason for the hydrops and the subsequent treatment. The exact reason for the hydrops fetalis remains unknown in about 25% of the cases.
Diagnosis of hydrops fetalis includes ultrasound, fetal blood sampling, and amniocentesis.
Basic treatment for the infant with hydrops fetalis includes extra delivery of oxygen or placement on a ventilator, removal of excess fluid in the cavities with a needle, and administering medications to help the kidneys get rid of the excess fluid.
Due to the serious nature of hydrops fetalis, your provider may elect to transfer your care to a tertiary care center. The fetus will be followed by a series of nonstress tests, and biophysical profiles. A nonstress test is painless and involves having a belt placed around the maternal abdomen which allows the provider to assess the fetal heart rate pattern. A biophysical profile is a special type of ultrasound which measures fetal well being. In addition, the fetus with immune hydrops fetalis will be followed with serial amniocentesis to see how much bilirubin is in the amniotic fluid. The goal is to keep the fetus in utero as long as possible to maximize fetal growth/weight and to enhance fetal lung maturity. Betamethasone may be administered to accelerate fetal lung maturity as the fetus may have to be delivered prior to term.
Your provider will give you a detailed explanation of this condition, and the implications.
Wishing you a safe and uneventful delivery, Pablo.