Polycythemia in Newborns (Too Many Red Blood Cells)
The short answer
Polycythemia occurs when a newborn has too many red blood cells, making the blood thicker than normal. It can cause a ruddy or deep red skin color and, in significant cases, can affect blood flow to organs. Risk factors include delayed cord clamping, maternal diabetes, and being small or large for gestational age. Most cases are mild and resolve without treatment.
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By Age
What to expect by age
Neonatal polycythemia is defined as a venous hematocrit above 65%. Risk factors include delayed cord clamping, twin-to-twin transfusion, maternal diabetes, growth restriction, and post-maturity. Your baby may appear deeply red or ruddy-colored (plethoric). Mild polycythemia usually requires only monitoring and adequate hydration through frequent feeding. Symptoms of significant polycythemia can include jitteriness, poor feeding, lethargy, rapid breathing, and in rare cases, low blood sugar or jaundice. Severe cases may require a partial exchange transfusion to reduce blood thickness.
Polycythemia typically resolves in the first few days to weeks as red blood cell levels normalize. As excess red blood cells are broken down, jaundice may develop. Your pediatrician will monitor bilirubin levels if needed. After resolution, there are generally no ongoing effects.
Polycythemia should be fully resolved. There are no lasting effects from mild to moderate neonatal polycythemia in most cases. Development should proceed normally.
No ongoing concerns related to neonatal polycythemia. Your baby should be developing normally.
What Should You Do?
When to take action
- Mild elevations in hematocrit without symptoms in a baby who is feeding and behaving normally
- A ruddy or red appearance in the first day or two that gradually normalizes
- Polycythemia that resolves with adequate feeding and hydration
- Your baby appears very red or deeply flushed
- You notice jitteriness, poor feeding, or unusual sleepiness in a baby with known polycythemia
- Your baby had risk factors for polycythemia and you want to ensure appropriate monitoring
- Baby with polycythemia develops respiratory distress, seizures, or significant lethargy
- Signs of low blood sugar (jitteriness, tremors, poor feeding) in a baby with known or suspected polycythemia
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Trust your instincts. If something feels wrong, reach out to your pediatrician.
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Related Medical Concerns
Anemia in Newborns
Anemia in newborns means the baby has fewer red blood cells or lower hemoglobin than normal. Causes include blood type incompatibility, blood loss, prematurity, and infections. Mild physiologic anemia is normal around 6-8 weeks as birth red blood cells are replaced. Signs of significant anemia include pallor, lethargy, poor feeding, and rapid breathing.
ABO Blood Type Incompatibility in Newborns
ABO incompatibility occurs when a mother and baby have different blood types (most commonly a type O mother with a type A or B baby), causing the mother's antibodies to attack the baby's red blood cells. This can lead to more severe jaundice and anemia in the newborn. It is manageable with monitoring and treatment, and the vast majority of babies do well.
Newborn Low Blood Sugar (Hypoglycemia)
Neonatal hypoglycemia (low blood sugar) is common in the first hours and days of life, especially in babies who are large or small for gestational age, premature, born to mothers with diabetes, or stressed during delivery. Mild hypoglycemia often responds to frequent feeding. More significant or persistent hypoglycemia may require IV glucose treatment. Early and frequent feeding is the best prevention.
My Baby's Head Shape Looks Abnormal
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Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.