Hydrops fetalis refers to fluid accumulation in several fetal compartments, serous cavities, or soft tissues. It is a serious symptom of several connatal conditions that cause anemia in the fetus. Hydrops fetalis can be diagnosed sonographically.
What is hydrops fetalis?
Hydrops fetalis is a term used in prenatal diagnosis and describes a generalized accumulation of fluid in the fetus. The fluid or edema is located in at least two fetal compartments, in serous body cavities such as the pleura, peritoneal cavity, and pericardium, or in soft tissues. The edema may be spread over large portions of the unborn child’s body. Hydrops fetalis occurs with a frequency of 1:1500 to 1:4000 pregnancies. Depending on the cause, a distinction is made between immunological and non-immunological hydrops fetalis; however, an assignment is only possible in approximately 50 percent of cases. Since the occurrence of fluid accumulation in the child indicates a chromosomal abnormality, an organic malformation or a severe disease of the fetus, hydrops fetalis is one of the sonographic soft markers during pregnancy. Based on these, serious diseases of the child can be diagnosed prenatally.
Causes
Hydrops fetalis is almost always caused by fetal anemia. This results in hypoxic damage to the capillary walls, increasing their permeability and causing fluid to leak from the intravascular space into the extravascular space. These anemias may be immunologic or non-immunologic in cause. Immunological causes include rhesus incompatibility between mother and child. This leads to massive hemolysis and anemia in the unborn child in second-term infants. Less common immunological causes are fetofetal transfusion syndrome and thalassemia. Meanwhile, predominantly non-immunological causes cause hydrops fetalis. For example, connatal malformations of the heart often result in fetal anemia. If cardiac output is increased to compensate for the anemia, heart failure and increased fluid retention may result. Infections with toxoplasmosis, syphilis connata, ringworm, or cytomegalovirus are also among the nonimmunologic causes. Furthermore, hydrops fetalis is frequently observed in a number of diseases such as Turner syndrome, trisomy 18, or Down syndrome.
Symptoms, complaints, and signs
The unborn child presents with fluid accumulation or edema in the fetal compartments, serous cavities, or soft tissues. The most common of these are ascites, pleural effusions, and polyhydramnios. Ascites, also abdominal dropsy, is the accumulation of water in the abdominal cavity. The pleura is a two-bladed skin that surrounds the lungs and lines the chest. Pleural effusion is when fluid accumulates in the narrow gap between the lungs and the chest wall. Polyhydramnios refers to a larger than average amount of amniotic fluid with an amniotic fluid index greater than 20 centimeters or an amniotic fluid deposit greater than eight centimeters. Fluid accumulation in the soft tissues occurs relatively early. In most cases, the fetus exhibits pumping weakness of the heart with increased cardiac output. After birth, the infants have increased neonatal jaundice; the anemia and edema are still present.
Diagnosis and course of the disease
The presence of hydrops fetalis is detected intrauterine by ultrasound. Clearly visible in the child is the detachment of the skin from the body due to the edema. If a risk factor for the development of fetal anemia is known, the pregnancy can be monitored by regular sonographic examinations to counteract hydrops fetalis if necessary. Blood sampling from the umbilical cord can indicate anemia at an early stage. A heart defect can be identified by echocardiography. Thanks to modern diagnostic and therapeutic options, approximately 85 percent of children can survive hydrops fetalis of immunological origin. However, if a nonimmunologic cause is present, fetal mortality exceeds 80 percent.
Complications
Hydrops fetalis can cause a variety of medical conditions. In many cases, the disease already affects the fetus.The affected person suffers from what is known as abdominal dropsy, whereby water accumulates in the abdominal cavity. This accumulation can later lead to breathing difficulties and further to shortness of breath. Likewise, water accumulation occurs in the soft tissues of the affected person. The heart is severely stressed by hydrops fetalis, so that damage and restrictions to the heart can occur. Furthermore, the liver is also damaged, so that most children are born with neonatal jaundice. If the symptoms are not treated, the patient usually dies prematurely. In most cases, treatment of hydrops fetalis is causal and symptomatic. Often the symptoms can be limited by blood transfusion. However, in severe cases, termination of the pregnancy is necessary if the mother’s health is also compromised. After birth, the children may need artificial respiration to survive. It is usually impossible to predict whether the disease will progress favorably.
When should you see a doctor?
The presence of hydrops fetalis is usually detected during ultrasound examinations during pregnancy. At the latest after birth, the condition can be detected by the typical external features. Whether further medical examinations are required after diagnosis depends primarily on the severity of the condition. Mild fluid retention sometimes recedes on its own. In severe cases, treatment must be initiated during pregnancy. Mothers who suffer from pain in the abdomen, possibly associated with unusual contractions of the baby, should talk to the gynecologist. If signs of a watery belly become apparent, the doctor must be consulted immediately. The condition must be clarified and treated immediately to rule out serious complications for mother and child. If the treatment is successful, no further treatment is required. However, the mother should continue to watch for any symptoms and at birth, if she has not already done so, inform the obstetricians at the hospital about hydrops fetalis. This will allow the baby to be examined immediately after birth and, if necessary, given the appropriate medications.
Treatment and therapy
Hydrops fetalis must be treated by correcting the cause. Usually, this is fetal anemia, which can be corrected intrauterine via the umbilical cord with blood transfusions. In the case of fetofetal transfusion syndrome during a twin pregnancy, the anastomoses in the blood circulation of the twins, which cause uneven blood distribution between the children, can be closed by laser coagulation. If hydrops fetalis is the result of a cause with a poor prognosis, a medical consultation is necessary to discuss with the parents the therapeutic options, the consequences for the child and especially the risks for the mother. Abortion for medical indication may need to be considered. If left untreated, hydrops fetalis not only has serious consequences for the child. In particularly severe cases, the mother may also develop symptoms that mirror hydrops fetalis. This clinical picture is called maternal hydrops syndrome and is symptomatically very similar to severe preeclampsia. Postnatally, infants suffering from hydrops fetalis require intensive medical care. Often, the infants require intubation and artificial respiration, receive blood transfusions, and are treated for jaundice with phototherapy or blood exchange. Ascites and pleural effusions are punctured for relief. This is followed by treatment of the causative disease to the extent possible.
Outlook and prognosis
The prognosis for hydrops fetalis is related to the cause of the water retention. If there is a congenital condition or a chromosomal abnormality in the fetus, it will be born with this underlying condition and the visible water retention may not have regressed by then either. Depending on the health of both mother and child, an incisional delivery may be appropriate in such cases so that neither is injured during delivery. If, in addition to the hydrops fetalis, the child is found to be so severely damaged that it would only be born handicapped or not viable at all, a late termination of the pregnancy may be considered.This is a very intimate and difficult decision, but in the case of disease triggers with very poor prognoses, it offers a way out of a life of suffering and pain for the unborn child. For the common cause of fetal anemia, a blood transfusion can be administered through the umbilical cord while the baby is still in the womb, significantly improving the baby’s prognosis. Other triggers of hydrops fetalis can also be treated during pregnancy so that the baby is born as healthy as possible and, at best, even a natural delivery is possible if the woman desires this type of delivery and feels safe doing so.
Prevention
Whether hydrops fetalis can be prevented depends largely on the cause of the fetal anemia. In cases of congenital malformations, only close sonographic monitoring of the pregnancy will help to intervene therapeutically at an early stage. Rhesus incompatibility can be counteracted by rhesus prophylaxis during the first pregnancy. This masks and degrades the fetal erythrocytes in the maternal blood without causing antibody formation. Vaccination protection or antibodies against infectious diseases should be checked as early as the time of childbearing.
Follow-up
Whether special measures of aftercare are available to the affected person in hydrops fetalis cannot be predicted in general, as these are highly dependent on the underlying disease. However, it is a serious condition that should be recognized and treated by a physician as soon as possible in any case. There is no cure on its own, and in the worst case scenario, the child may die if hydrops fetalis is not treated. In some cases, hydrops fetalis requires termination of the pregnancy. After such an abortion, in most cases the parents need psychological support. Especially the help and support from their own family or friends is very important to prevent depression and other psychological upsets. If the child survives the birth, he or she will need permanent medical monitoring. Even then, the parents usually depend on psychological support. The parents must strongly encourage the child’s further development to counteract damage and prevent further complications. In this context, no general prediction can be made about the further life expectancy of the child.
What you can do yourself
The disease hydrops fetalis cannot be treated by means of self-help. In this case, a visit to a doctor is always necessary. If no treatment occurs, the unborn children may die from this disease. In some cases, this may require complete termination of the pregnancy if treatment would be too risky for the mother. For this reason, self-help is limited to the treatment of possible psychological complaints. Here, detailed discussions with one’s own partner, family or, of course, friends can be very helpful in preventing or treating depression and other psychological upsets. However, such conversations do not replace professional therapy by a therapist. Therefore, if they are not helpful, a psychologist should be consulted. Contact with other affected parents can also be helpful. This often leads to an exchange of information, which can possibly improve the quality of life of the affected person and thus make everyday life easier. Likewise, a visit to a self-help group can be worthwhile to talk about the disease.
