What are the symptoms of ABO incompatibility?
Last updated September 7, 2026.
ABO incompatibility shows up either as a sudden reaction during a blood transfusion, with fever, chills, back or chest pain and dark urine, or as jaundice in a newborn during the first day of life. Which set of symptoms you see depends on the setting. A transfusion reaction from mismatched blood usually begins within minutes of the transfusion starting, which is why staff stay close and check vital signs early. In a newborn, the picture is quieter: yellowing of the skin and eyes in the first 24 hours, sleepiness, poor feeding, and pale color. Knowing your own blood type and making sure it is on file at your hospital and in your prenatal records helps your care team catch a mismatch before it matters. Newborn jaundice that appears on day one is always checked with a bilirubin test rather than by eye alone.
What to do
- Speak up during a transfusion: Tell the nurse right away if you feel chills, back pain, itching, or shortness of breath after a transfusion starts.
- Know the timing: Transfusion reactions from ABO mismatch typically begin in the first 15 minutes, so the early part of a transfusion is monitored most closely.
- Check a newborn in daylight: Look at the skin, the whites of the eyes, and the gums, and call your pediatrician the same day if yellowing appears in the first 24 hours.
- Track feeding and alertness: A baby who is hard to wake, feeds poorly, or has fewer wet diapers than expected should be seen promptly.
- Keep your blood type on record: Make sure your blood type is documented in your chart and prenatal records, and ask for a type and screen before planned surgery.
- Go to emergency care for red flags: Chest pain, trouble breathing, fainting, or red or brown urine after a transfusion are emergency symptoms.
Related questions
- Blood clot in leg symptoms
- Can abo incompatibility go away on its own
- Can an online doctor help with menopause symptoms
- Can i see what my doctor wrote about me