Megaloblastic Anemia

What is megaloblastic anemia?

Megaloblastic anemia is a type of anemia characterized by very large red blood cells. In addition to the cells being large, the inner contents of each cell are not completely developed. This malformation causes the bone marrow to produce fewer cells, and sometimes the cells die earlier than the 120-day life expectancy. Instead of being round or disc-shaped, the red blood cells can be oval.


There are many causes of megaloblastic anemia, but the most common source in children occurs from a vitamin deficiency of folic acid or vitamin B-12. Other sources of megaloblastic anemia include the following:

  • Digestive diseases — Certain diseases of the lower digestive tract can lead to megaloblastic anemia. These include celiac disease, chronic infectious enteritis, and enteroenteric fistulas. Pernicious anemia is a type of megaloblastic anemia caused by an inability to absorb Vitamin B-12 due to a lack of intrinsic factor in gastric (stomach) secretions. Intrinsic factor enables the absorption of Vitamin B-12.
  • Malabsorption Inherited congenital folate malabsorption, a genetic problem in which infants cannot absorb folic acid in their intestines, can lead to megaloblastic anemia. This requires early intensive treatment to prevent long-term problems such as intellectual disabilities.
  • Medication-induced folic acid deficiency Certain medications, specifically ones that prevent seizures, such as phenytoin, primidone and phenobarbital, can impair the absorption of folic acid. The deficiency can usually be treated with a dietary supplement.
  • Folic acid deficiency Folic acid is a B vitamin required for the production of normal red blood cells. Folic acid is present in foods such as green vegetables, liver and yeast. It is also produced synthetically and added to many food items.

Signs and symptoms

Children with megaloblastic anemia may experience different symptoms and symptoms may vary in severity. Some of the most common symptoms of megaloblastic anemia include: 

  • Abnormal paleness or lack of color of the skin
  • Decreased appetite
  • Irritability
  • Lack of energy or tiring easily (fatigue)
  • Diarrhea
  • Difficulty walking
  • Numbness or tingling in hands and feet
  • Smooth and tender tongue
  • Weak muscles

The symptoms of megaloblastic anemia may resemble other blood conditions or medical problems. Always consult your child's physician for a diagnosis.

Testing and diagnosis

Diagnosing megaloblastic anemia begins with a complete medical history and physical examination of your child. In addition, several blood tests can be performed to confirm the diagnosis. If the megaloblastic anemia is thought to be caused from a problem in the digestive tract, a barium study of the digestive system may be performed.


Specific treatment for megaloblastic anemia will be determined by your child's physician based on:

  • Your child's age, overall health and medical history
  • Extent of the anemia
  • Cause of anemia
  • Your child's tolerance for specific medications, procedures or therapies
  • Expectations for the course of the anemia
  • Your opinion or preference

Treatment usually involves your child taking an oral dietary folic acid supplement for at least two to three months. If the disorder is caused by an absorption problem in the digestive tract, this may need to be treated first.

Follow-up care

Your child with megaloblastic anemia may need to adjust their diet long-term to include foods that are rich in folic acid and/or B-12.

Foods that are rich in folic acid include the following:

  • Orange juice
  • Oranges
  • Romaine lettuce
  • Spinach
  • Liver
  • Rice
  • Barley
  • Sprouts
  • Wheat germ
  • Soy beans
  • Green, leafy vegetables
  • Beans
  • Peanuts
  • Broccoli
  • Asparagus
  • Peas
  • Lentils
  • Wheat germ
  • Chick peas (garbanzo beans)

Foods that are rich in folic acid and vitamin B-12 include the following:

  • Eggs
  • Meat
  • Poultry
  • Milk
  • Shellfish
  • Fortified cereals

Next Steps