🫧
Patient Education
Understanding
Hydrops Fetalis
How we evaluate and care for your baby
Based on SMFM Consult Series #75 · 2026
What Is It?
What Is Hydrops Fetalis?
Extra fluid collecting in your baby's body — in the skin, belly, lungs, or around the heart.
Hydrops is detected on ultrasound — it is not caused by anything you did.
Prevalence
How Common Is It?
1 in 1,700
pregnancies affected
by non-immune hydrops
90%
of hydrops cases are
non-immune (not blood type)
Many
possible causes —
we will search for yours
You are not alone. Our team has experience caring for families facing this diagnosis.
Causes
What Can Cause Hydrops?
🧬
Genetic Conditions
Chromosomes or single-gene disorders
❤️
Heart Problems
Structure or rhythm of the heart
🦠
Infections
Parvovirus, CMV, toxoplasmosis
🩸
Fetal Anemia
Low red blood cell count in baby
🫁
Lung or Chest Masses
Growths pressing on blood vessels
🩺
Placenta Issues
Tumors or blood vessel problems
Our Plan
Our Evaluation Plan
We follow a step-by-step approach to find the cause and guide your care.
🔬
Step 1 · Detailed Ultrasound
Full survey of baby's anatomy, heart, and fluid areas
🧬
Step 2 · Genetic Testing
Amniocentesis for chromosomes and gene analysis
🦠
Step 3 · Infection Testing
Blood tests for parvovirus, CMV, toxoplasmosis, syphilis
🩸
Step 4 · Anemia Check
MCA Doppler ultrasound to measure baby's blood flow
❤️
Step 5 · Fetal Echocardiogram
Detailed ultrasound of baby's heart structure and rhythm
Step 1
Detailed Ultrasound
What We Look For
- 🫧 Fluid in belly, chest, or skin
- 🫀 Heart structure and rhythm
- 🫁 Lung or chest masses
- 🧠 Brain and spine development
- 🩺 Placenta and umbilical cord
- 💧 Amniotic fluid level
MCA Doppler
- 🩸 Measures blood flow in baby's brain artery
- 📊 Detects signs of anemia (low blood count)
- ✅ Safe, painless ultrasound measurement
- 🔄 May be repeated over time
Ultrasound is safe for you and your baby. It gives us critical information.
Step 2
Genetic Testing
Finding a genetic cause helps us understand the prognosis and plan for future pregnancies.
| Test |
What It Checks |
How Done |
| Chromosomal Microarray (CMA) |
Extra or missing chromosome pieces |
Amniocentesis |
| Karyotype |
Chromosome number & structure |
Amniocentesis |
| Exome / Genome Sequencing |
Single-gene disorders (e.g., Noonan syndrome) |
Amniocentesis or blood |
| Gene Panel |
Targeted group of known disorder genes |
Amniocentesis or blood |
SMFM recommends offering genetic testing for all pregnancies with fetal fluid collections.
Step 3
Testing for Infections
Infections account for about 7–8% of hydrops cases. Many are treatable.
🦠
Parvovirus B19
Most common infectious cause; can cause fetal anemia
🔬
Cytomegalovirus (CMV)
Common virus; tested via blood or amniotic fluid
🦟
Toxoplasmosis
Parasite; blood test performed
🩺
Syphilis
Routine blood test; highly treatable
If an infection is found, treatment options are available to protect your baby.
Step 4
Checking for Fetal Anemia
Anemia (low red blood cells) is a treatable cause of hydrops.
Normal Result
- ✅ Blood flow is within normal range
- ✅ No immediate concern for anemia
Elevated Result
- ⚠️ May indicate low red blood cells
- 🩸 Cord blood sampling may be needed
- 💉 Intrauterine transfusion may help
Step 5
Fetal Echocardiogram
A detailed ultrasound of your baby's heart — structure, valves, and rhythm.
❤️
Heart Structure
Checks chambers, valves, and vessels
📡
Heart Rhythm
Detects fast or slow heartbeat (arrhythmia)
💧
Pericardial Fluid
Fluid around the heart is measured
🏥
Treatment Planning
Some arrhythmias can be treated with medication
Heart problems causing hydrops can sometimes be treated during pregnancy.
Prognosis
What Affects the Outcome?
Outcomes vary widely and depend on the underlying cause.
More Favorable Causes
- ✅ Parvovirus (treatable anemia)
- ✅ Fetal arrhythmia (medication)
- ✅ Lung masses (surgery after birth)
- ✅ Lymphatic problems
Requires Close Monitoring
- ⚠️ Genetic syndromes
- ⚠️ Heart defects
- ⚠️ Metabolic disorders
- ⚠️ Unknown cause
Our team will give you individualized counseling based on your baby's specific findings.
Management
Your Care Options
Care is individualized to you, your baby, and the underlying cause.
🔄
Close Monitoring
Serial ultrasounds and maternal blood pressure checks
💉
Fetal Transfusion
For anemia — blood given directly to baby
💊
Medications
Treat arrhythmias through mother's bloodstream
🏥
Specialized Delivery
Level III/IV NICU center for complex cases
🤝
Palliative Care
Compassionate support when treatment is not the goal
👶
Neonatology Team
Specialists ready at delivery for your baby
Delivery
Planning for Delivery
Delivery timing is individualized. We avoid early delivery unless medically necessary.
When Early Delivery May Be Needed
- ⚠️ Worsening hydrops on ultrasound
- ⚠️ Preterm labor or water breaking
- ⚠️ Mirror syndrome (maternal preeclampsia)
- ⚠️ Non-reassuring fetal testing
Delivery Location
- 🏥 Level III or IV NICU center preferred
- 👶 Neonatology team present at birth
- 🩺 Mode of delivery individualized
- 💊 Steroids given if preterm delivery expected
Our goal is to keep you and your baby safe while giving the best chance for a good outcome.
Your Team
Your Care Team
You will be supported by a team of specialists working together.
👩⚕️
Maternal-Fetal Medicine
High-risk pregnancy specialist (MFM)
🧬
Genetic Counselor
Guides testing and interprets results
👶
Neonatologist
Newborn intensive care specialist
❤️
Pediatric Cardiologist
Heart specialist for your baby
You are never alone. Every decision is made together with you at the center.
🤝
Partnership
We Are Here for You
Every question matters. Every concern is heard. We walk this journey with you.
📋
Ask us about
your test results
🗓️
Schedule follow-up
appointments
📞
Call us with
any concerns
Atlanta Perinatal Associates · Based on SMFM Consult Series #75 (2026)