Rh Incompatibility: Causes, Signs and Symptoms, Prevention & Treatment
Introduction
Rh incompatibility is one of the most important conditions related to pregnancy and newborn health. It occurs when a mother with Rh-negative blood carries a baby with Rh-positive blood, inherited from the father. Although the condition can be serious, medical advancements—especially the Anti-D immunoglobulin injection—have made Rh incompatibility highly preventable.
This detailed and SEO-optimized article explains the causes, symptoms, risk factors, diagnosis, prevention, and treatment of Rh incompatibility. It also includes helpful FAQs for students, parents, and healthcare readers.
What is Rh Incompatibility?
Rh incompatibility (also known as Rhesus incompatibility) is a condition that occurs when:
The mother is Rh-negative,
The fetus is Rh-positive, and
The mother’s immune system forms antibodies against the baby’s Rh-positive blood cells.
These antibodies cross the placenta and attack the baby’s red blood cells, causing hemolytic disease of the newborn (HDN), also called erythroblastosis fetalis.
Rh incompatibility does not affect the first pregnancy in most cases.
It becomes dangerous in subsequent pregnancies if not managed properly.
Understanding the Rh Factor
The Rh factor is a protein found on the surface of red blood cells.
If present → Rh-positive
If absent → Rh-negative
Most people in India and worldwide are Rh-positive.
Blood type examples:
A+, B+, O+, AB+ → Rh-positive
A−, B−, O−, AB− → Rh-negative
Rh-negative mothers carrying Rh-positive babies require special monitoring.
Causes of Rh Incompatibility
Rh incompatibility occurs when Rh-negative mother is exposed to Rh-positive fetal blood.
This exposure is called sensitization or isoimmunization, leading the mother to form anti-Rh antibodies.
Causes of Sensitization Include:
1. Pregnancy and Delivery
During childbirth, the baby’s Rh-positive blood can mix with the mother’s blood.
This is the most common cause.
2. Miscarriage or Abortion
Any loss of pregnancy (spontaneous or induced) can expose maternal blood to fetal Rh-positive blood.
3. Ectopic Pregnancy
Even early ectopic pregnancy can cause sensitization.
4. Amniocentesis or Chorionic Villus Sampling (CVS)
Invasive prenatal tests may cause fetal cells to enter maternal circulation.
5. Placental Abruption
Separation of placenta can leak fetal blood into mother’s bloodstream.
6. Trauma to Abdomen
Examples:
Accident
Fall
Blow to the stomach
These can cause fetomaternal hemorrhage.
7. Blood Transfusion
Receiving Rh-positive blood by mistake (very rare today) can lead to sensitization.
How Does Rh Incompatibility Affect Pregnancy?
When fetal Rh-positive cells enter an Rh-negative mother:
1. Her immune system identifies them as “foreign.”
2. She produces IgG anti-Rh antibodies.
3. These antibodies cross the placenta during future pregnancies.
4. They destroy fetal red blood cells → hemolysis.
This leads to hemolytic disease of the newborn (HDN).
Signs and Symptoms of Rh Incompatibility
Rh incompatibility usually shows no symptoms in the mother.
Symptoms appear primarily in the fetus or newborn.
Signs and Symptoms in the Fetus:
1. Anemia
Destruction of red blood cells leads to severe fetal anemia.
2. Enlarged Liver and Spleen
The fetus tries to produce more RBCs → organ enlargement.
3. Hydrops Fetalis (Severe Complication)
Life-threatening condition where:
Excess fluid collects in body tissues
Severe swelling
Heart failure
Hydrops is a medical emergency.
Signs and Symptoms in the Newborn:
1. Jaundice
Yellowing of skin and eyes
Occurs within 24 hours of birth
2. Pale Skin
Due to anemia.
3. Difficulty Breathing
Related to anemia and organ enlargement.
4. Heart Failure
In severe cases.
5. Swelling of the Body
Fluid accumulation indicates hydrops.
6. Seizures
Due to high bilirubin levels affecting the brain (kernicterus).
7. Lethargy & Poor Feeding
Common in infants with anemia and hyperbilirubinemia.
Risk Factors for Rh Incompatibility
A woman is at risk if she is:
Rh-negative
Partner is Rh-positive
Has had previous pregnancies
Had miscarriage/abortion
Underwent invasive procedures
History of abdominal trauma
Did not receive Anti-D injection in previous pregnancy
Diagnosis of Rh Incompatibility
1. Blood Group and Rh Typing
Performed early in pregnancy.
2. Indirect Coombs Test (ICT)
Detects maternal anti-Rh antibodies.
Repeated throughout pregnancy.
3. Direct Coombs Test (DCT)
Done on newborn’s blood after delivery.
Confirms hemolytic disease.
4. Ultrasound
Detects:
Fetal anemia
Organ enlargement
Hydrops fetalis
5. Doppler Ultrasound (MCA Doppler)
Measures blood flow in fetal brain → detects anemia early.
6. Amniocentesis (rare now)
Used to measure fetal bilirubin levels.
Complications of Rh Incompatibility
Without treatment, Rh incompatibility can lead to:
1. Fetal Anemia
Can become life-threatening.
2. Hydrops Fetalis
Severe form of fetal heart failure.
3. Premature Delivery
Due to complications.
4. Stillbirth
In extreme cases.
5. Kernicterus
Brain damage from high bilirubin.
6. Neonatal Death
If untreated.
Prevention of Rh Incompatibility
Prevention is highly effective and simple.
1. Anti-D Immunoglobulin Injection (RhIg or RhoGAM)
This injection prevents the mother from producing antibodies.
When Anti-D is Given?
A. During Pregnancy
At 28 weeks
After any bleeding
After abdominal trauma
After invasive procedures (CVS, amniocentesis)
B. After Delivery
Within 72 hours if the baby is Rh-positive
C. After Miscarriage or Abortion
Anti-D is essential even in early pregnancy loss.
D. After Ectopic Pregnancy
Rh-negative women must receive Anti-D.
2. Routine Antenatal Testing
Early identification reduces risk.
3. Avoid Mixing Mother’s and Fetus’s Blood
Care during delivery, trauma, and medical procedures.
Treatment of Rh Incompatibility
If the mother is already sensitized, treatment focuses on the fetus/newborn.
1. Fetal Monitoring
Regular ultrasound + MCA Doppler to monitor anemia.
2. Intrauterine Blood Transfusion (IUT)
Performed between 18–35 weeks when severe anemia is detected.
Blood is transfused directly to the fetus.
This is life-saving and highly effective.
3. Early Delivery
If fetus is mature and anemia is worsening.
4. Treatment After Birth
Phototherapy
Reduces bilirubin.
Exchange Transfusion
Baby’s blood is replaced to remove antibodies and bilirubin.
Oxygen & Ventilation
For infants with breathing difficulty.
IV Fluids and Electrolyte Support
Management of Jaundice and Anemia
Continuous monitoring.
Prognosis
With timely Anti-D injection, Rh incompatibility is 90–95% preventable.
With proper treatment, most babies recover fully, especially when diagnosed early.
Lifestyle and Care Tips for Rh-Negative Pregnant Women
Never miss antenatal checkups.
Always inform your doctor you are Rh-negative.
Get Anti-D on time.
Avoid home deliveries—hospital monitoring is essential.
Seek immediate care if you have bleeding or abdominal trauma.
Ensure proper post-delivery follow-up.
Frequently Asked Questions (FAQs)
1. What causes Rh incompatibility?
It occurs when an Rh-negative mother is exposed to Rh-positive fetal blood, leading her to produce antibodies.
2. What is the main prevention for Rh incompatibility?
The Anti-D immunoglobulin injection at 28 weeks and after delivery.
3. Can Rh incompatibility affect the first pregnancy?
Usually no, unless the mother was exposed to Rh-positive blood earlier.
4. What are the symptoms of Rh disease in newborns?
Jaundice, anemia, pale skin, swelling, breathing difficulty, and in severe cases, hydrops fetalis.
5. How is Rh incompatibility diagnosed?
Blood typing, Indirect Coombs test, ultrasound, and newborn testing.
6. Can an Rh-negative mother have an Rh-positive baby?
Yes, if the father is Rh-positive or heterozygous.
7. What happens if Anti-D injection is not taken?
The mother may become sensitized, increasing risks in future pregnancies.
8. Is Rh incompatibility curable?
It is preventable. Once sensitization has happened, the condition is manageable but not reversible.
9. Is Rh incompatibility dangerous?
If untreated, it can lead to severe anemia, hydrops, or newborn death.
10. Can Rh incompatibility be detected early?
Yes, through routine antenatal blood tests.
Conclusion
Rh incompatibility is a preventable but potentially serious pregnancy complication. Awareness, timely testing, and especially Anti-D immunoglobulin have drastically reduced its risks. With proper antenatal care, early diagnosis, and correct treatment, most affected newborns recover fully.
Understanding your blood group and following your doctor’s advice can ensure a safe and healthy pregnancy.