Makindo Medical Notes

🧾 About

• Hydrops Fetalis is a severe fetal condition defined by abnormal fluid accumulation in two or more body compartments (e.g., ascites, pleural effusion, pericardial effusion, skin oedema).
• If untreated, it can cause fetal heart failure, organ damage, or stillbirth.
• Represents the end stage of many fetal pathologies rather than a single disease.

⚙️ Aetiology

• Immune: Classic cause = erythroblastosis fetalis (Rh isoimmunisation → maternal anti-D IgG destroys fetal RBCs → severe anaemia + hydrops).
• Non-Immune: More common today due to anti-D prophylaxis. Causes include:
  • Chromosomal anomalies (Turner’s, trisomies).
  • Fetal heart/lung malformations.
  • Congenital infections (parvovirus B19, CMV, syphilis, toxoplasmosis).
  • Liver disease, metabolic disorders, thoracic masses.

⚠️ Risk Factors

• Rh-negative mother carrying an Rh-positive fetus (immune hydrops).
• Previous blood product exposure → alloimmunisation.
• Maternal conditions: collagen vascular disease, severe diabetes, substance abuse, medications (e.g., indomethacin).
• Maternal extremes of age: <16 years or >35 years.

🩺 Clinical Presentation (Fetal/Neonatal)

• Severe fetal anaemia → high-output cardiac failure.
• Hepatosplenomegaly from extramedullary haematopoiesis.
• Gross ascites, pleural/pericardial effusions, and generalised oedema (“hydropic fetus”).
• Polyhydramnios, placental thickening, and maternal “mirror syndrome” (pre-eclampsia-like picture) may occur.

🔍 Investigations

• Ultrasound: Fluid in ≥2 compartments, placental thickening, hepatosplenomegaly, polyhydramnios.
• MCA Doppler: ↑ Peak systolic velocity → fetal anaemia (preferred non-invasive test).
• Fetal blood sampling: Assess Hb and haematocrit, consider intrauterine transfusion.
• Amniocentesis: For karyotype, genetic testing, infection screen.

💊 Management

• Prevention: Anti-D immunoglobulin to Rh-negative mothers prevents immune hydrops.
• Antenatal:
  • Intrauterine transfusion for severe fetal anaemia.
  • Treat underlying cause (e.g., maternal infection).
• Delivery: Often by Caesarean if fetus viable and distressed; prepare for resuscitation.
• Neonatal Care:
  • Ventilation and oxygen therapy for respiratory distress.
  • Exchange or top-up transfusions for anaemia.
  • Drainage of ascites/pleural effusions.
  • Glucose support for hypoglycaemia.
  • Vitamin K and diuretics (e.g., furosemide) if indicated.

💡 Teaching Pearls

• Immune hydrops has declined dramatically thanks to anti-D prophylaxis → now most cases are non-immune.
• MCA Doppler is the key non-invasive tool to detect fetal anaemia early.
• Mirror syndrome (maternal oedema mimicking pre-eclampsia) is a unique complication worth remembering.
• In exams, think: “fluid in ≥2 compartments” = hydrops fetalis.

📚 References

• RCOG Green-top Guideline 65: Management of Women with Red Cell Antibodies in Pregnancy.
• UpToDate: Nonimmune hydrops fetalis.
• Williams Obstetrics, 25th Edition.