Fetal swelling is not a specific disease entity. It is a pre-sign symptom of a whole range of fetal developmental abnormalities, accompanied by the presence of isolated or generalized transudates and / or edema of the fetal and postpartum tissues that arise during the intrauterine life. What are the symptoms of fetal edema? What is the procedure and prognosis?

Fetal swellingcan also indicate the presence of leakage into one of the body cavities or generalized swelling. In such a situation, the presence of edema of the placental and subcutaneous tissue, as well as the presence of exudates into the peritoneal cavity (ascites), pleura (pleurisy) and pericardium.

The frequency of fetal edema is estimated from 1: 1,500 to 1: 7,000 births.

It is worth mentioning here that fetal edema is more often diagnosed in reference ultrasound centers to which patients with suspected fetal developmental anomalies are referred.

Fetal swelling: causes

The formation of swelling of the fetal tissues and exudation into the body cavities may be triggered by several different pathomechanisms. The most important of these include increased pressure in the venous system, decreased protein synthesis or loss, increased capillary permeability, and lymphatic obstruction.

The chance of survival is only a dozen or so to twenty percent of the fetuses in which it is possible to determine the cause of the edema and to treat it effectively in the prenatal period.

Increased pressure in the venous system is usually a symptom of circulatory failure, which results from the dysfunction of the fetal heart, its developmental defect, or failure in the course of severe anemia or myocarditis.

In addition, the increase in venous pressure may be the result of pressure on the vessel by a tumor (e.g. liver hemangioma) or the presence of a blood clot in the inferior vena cava.

Congenital defects or diseases of the liver and kidneys of the fetus lead to a decrease in protein synthesis and their excessive loss, which results in a reduction of oncotic blood pressure and the formation of edema.

Another important pathomechanism is the increase in the permeability of capillaries, resulting from severe, chronic hypoxia, which mayoccur e.g. in the course of an infection.

Lymphatic obstruction, often seen in Turner syndrome, can cause fetal tissue swelling, on the one hand, and the characteristic lymphatic cysts in the neck, on the other.

In addition, fetal swelling may be a result of the presence of vascular leakage in arteriovenous fistulas or of the twins' steal syndrome.

In this syndrome, the donor fetus is limited in intrauterine development and has polyhydramnios, while the recipient fetus is hyperhydrated - has the features of generalized edema and has polyhydramnios.

These changes are the result of volume overload in the recipient fetus and the presence of congestive heart failure.
There are many diseases that accompany fetal edema. They are listed below.

1. Cardiovascular causes

Developmental defects

  • underdevelopment of the left ventricle
  • common atrioventricular canal
  • underdevelopment of the right ventricle
  • atrial septal defect
  • ventricular septal defect
  • single-chamber heart
  • transpose large vessels
  • tetralogy of Fallot
  • Ebstein defect
  • premature closure of the foramen ovale or ductus arteriosus
  • common arterial trunk
  • regurgitation of pulmonary valves
  • Subendocardial fibroelastosis

Tachycardia

  • atrial flutter
  • paroxysmal atrial tachycardia
  • Wolff-Parkinson-White syndrome
  • supraventricular tachycardia

Brachyarrhythmia
Other arrhythmias
Arteriovenous fistulas

  • neuroblastoma
  • sacral teratoma
  • large hemangiomas of the fetus and umbilical cord
  • chorioangioma

Blood clots and vessel sealing

  • occlusion of the inferior vena cava, portal vein, femoral veins, renal veins

Rhabdomyosarcoma of the heart
Other heart cancers
Cardiomyopathies

2. Chromosomal defects

Monosomy 45 X
Trisomy 13, 18, 21
Turner syndrome (mosaicism 45 X0, 46 XX)
Triploidy
Other anomalies

3. Bone dysplasias

Fatal dwarfism
Hypophosphatasia
Osteogenesis imperfecta
Achondrogenesis
Congenital joint stiffness

4. Multiple pregnancy

Twin Stealing Syndrome
Cardless twin

5. Hematological causes

Fetal and maternal leakage
Bleeding into body cavities
Alpha-thalassemia
Glucose-6-phosphatase deficiency
Other defectsenzymatic red blood cells
Hemophilia A

6. Metabolic diseases

Gaucher disease
Gangliosidosis GM1

7. Infections

Parvovirus B19
Cytomegaly
Toxoplasmosis
Syphilis
Herpes Type 1
Rubella
Hepatitis Leptospirosis

8. Lung defects

Diaphragmatic hernia
Congenital cystic lung disease
Mediastinal teratoma
Lung hypoplasia
Pulmonary hemangioma
Lung sequestration
Bronchial obstruction
Bronchial cysts

9. Liver defects

Liver calcification
Liver fibrosis
Liver cystic disease
Biliary obstruction
Familial cirrhosis

10. Urinary system defects

Urethral stricture, urethral atresia
Posterior urethral valve
Congenital nephrotic syndrome
Dried plum syndrome
Spontaneous bladder rupture

11. Gastrointestinal defects
Intestinal atresia
Intestinal torsion
Duplication of the gastrointestinal tract
Undefined turn of the gastrointestinal tract
Meconium peritonitis

12. Maternal causes

Unbalanced severe diabetes
Severe anemia
Hypoproteinemia
Tecalutein cysts

13. Iatrogenic causes

Closure of the arterial duct after administration of indomethacin

Fetal swelling: diagnosis

Generalized fetal swelling can be identified by ultrasound examination. The sensitivity of this study in the diagnosis of this pathology reaches 100%. Moreover, most diagnoses are made during routine screening.

The typical features of the developed form of generalized fetal edema include:

  • hyperplacentosis, i.e. thickening of the placenta over 4 cm
  • thickening of the subcutaneous tissue greater than 5 mm
  • fluid in the peritoneal cavity
  • pleural effusion
  • fluid in the pericardial cavity
  • polyhydramnios, which occurs in about 50-75% of fetuses with this pathology.

It is one of the basic causes of premature births occurring in almost all cases.

Fetal edema can be diagnosed when there is a significant degree of transudation into two body cavities or the presence of transudate in one body cavity and swelling of the subcutaneous tissue.

The presence of generalized edema of the subcutaneous tissue is a prognostic negative factor.

The presence of an isolated peritoneal exudate is most often associated with developmental abnormalities in the urinary or gastrointestinal tract. The prognosis in these cases is better, and the managementdepends on the diagnosis of the root cause of the edema.
Isolated pleural effusion is most often associated with lymphatic abnormalities and is formed by the accumulating lymph.

It is worth knowing that early onset of changes and coexistence of pleural effusion with other symptoms of generalized edema are unfavorable.

A more favorable prognosis is one-sided and remission effusion. The presence of fluid in the pleural cavities of the fetus with generalized edema is of particular importance - it is associated with the risk of pulmonary hypoplasia.

Finally, it is worth adding that the isolated pericardial effusion may be the first, prodromal symptom of cardiogenic generalized edema.

Fetal Edema: Differential Diagnosis

The following groups of tests are used in the differential diagnosis:

  • fetal ultrasound
  • maternal biochemical and serological tests
  • amniotic fluid testing
  • testing of a fetal blood sample.
Important

Despite the fact that so many diagnostic tests can be carried out, it is often impossible to establish the cause of a fetal swelling.

Moreover, due to the fact that virtually all fetuses with idiopathic edema die intrauterine or immediately after birth, it is extremely important to perform a thorough post-mortem examination, which may guide medical management in the event of a repeated occurrence of this pathology in the next pregnancy.

Ultrasound examination, in addition to assessing the severity of edema, allows the exclusion of other co-occurring structural defects.

Complete fetal anatomy studies should be performed, with particular emphasis on the anatomy of the heart, intracardiac blood flow, and vascular blood flow parameters.

The coexistence of fetal edema and its structural defects significantly worsens the prognosis.

In the case of the presence of generalized fetal edema, it is recommended to perform serological tests of the pregnant woman in order to exclude the presence of antibodies that may cause hemolytic disease of the fetus.

Other serological tests such as VDRL (syphilis infection test), rubella, toxoplasmosis, parvovirosis and cytomegalovirus tests should not be forgotten.

In special situations, with repeated fetal edema in subsequent pregnancies, it is advisable to perform an HLA histocompatibility analysis of the parents - high antigen compliance may cause the edemageneralized fetuses.

If fetal edema is diagnosed in the first half of pregnancy, amniotic fluid tests are performed in further diagnostics - thanks to the cells it contains, it is possible to assess the fetal karyotype.

In addition, you can assess the concentration of alpha-fetoprotein in the amniotic fluid (it is used to assess the occurrence of structural defects in the fetus), perform its culture, and if metabolic defects are suspected - conduct tests for enzymatic defects.

The diagnosis of fetal edema after 24 weeks of pregnancy means that the diagnosis of this pathology is based on the assessment of the fetal blood obtained by puncture of the fetal vessel.

The following tests should be performed on the collected blood sample:

  • morphology with smear and platelets
  • genetic tests (karyotype, possibly metabolic tests)
  • protein concentration test
  • proteinogram
  • assessment of IgM antibody concentration
  • isolation of the parvovirus genome by PCR
  • if alpha thalassemia is suspected - hemoglobin chain analysis.

Fetal swelling: treatment

The determination of the etiological factor that led to the fetal edema undoubtedly influences the further management and prognosis.

Usually, fetuses with isolated ascites or a pleural effusion have good prognosis.

Severe swelling caused by anemia also offers a chance of recovery.

In such a situation, multiple red blood cell transfusions supplemented with albumin solution are performed.

Also, fetuses with swelling resulting from cardiac arrhythmias have a chance of receiving prenatal treatment.

On the other hand, the demonstration of structural anomalies of the fetal heart is unfavorable.

If it is not possible to determine the cause of fetal edema, its termination should be considered in the first half of pregnancy.

In the second half of pregnancy, prenatal therapy is attempted.

For this purpose, red blood cell transfusions, antiarrhythmic drugs in the presence of fetal heart rhythm disturbances, albumin transfusions or decompression punctures of the pleural and peritoneal cavities of the fetus are used.

It is worth knowing that in the case of not very advanced edema changes, earlier termination of pregnancy (around 34 weeks of its duration) may be considered, but usually contractile activity of the uterus occurs at an earlier stage.

Due to the ultimately unfavorable prognosis, it is not advisable to perform a caesarean section due to the impending asphyxiaintrauterine tissue of the fetus.

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Pregnancy