anemia of prematurity

Anemia of Prematurity: A Condition Affecting Preterm Infants

Anemia of prematurity (AOP) is a common condition that affects preterm infants, characterized by a lack of red blood cells and low hemoglobin levels. This condition occurs due to the impaired ability of preterm infants to increase serum erythropoietin (EPO), a hormone responsible for producing red blood cells.

Causes and Contributing Factors

The primary cause of AOP is the impaired ability to increase serum EPO appropriately in response to anemia and decreased oxygen levels. Other contributing factors include:

• Untimely birth: Preterm infants are born before their bodies have completed the process of erythropoiesis, leading to a lack of red blood cells.
• Blood loss during delivery: Blood loss experienced during delivery can contribute to AOP.
• Shortened life span of fetal blood cells: Fetal blood cells in preterm infants have a shorter lifespan (35-50 days) compared to adult blood cells.
• Acclimation to a relatively hyperoxic environment outside the womb: The transition from the womb's hypoxic environment to the more oxygen-rich environment outside can lead to a decrease in EPO production.

Characteristics and Timeline

AOP is characterized by:

• Normocytic, normochromic, hyporegenerative anemia: A lack of red blood cells with normal cell size and color.
• Low serum EPO level: Despite the low hemoglobin concentration, preterm infants often have a remarkably reduced EPO level.

The condition typically resolves within 3-6 months post-birth as the infant's body adapts to the external environment. However, in some cases, multiple red blood cell transfusions may be necessary during the first few weeks of life.

References

• [1] Result: a blood disorder characterized by low hemoglobin levels in premature neonates that usually spontaneously resolves within 3-6 months post birth; a combination of factors including the transition from the liver to the bone marrow for erythropoiesis in a neonate, blood loss experienced during delivery, the shortened life span of fetal blood cells, and an acclimation to a relatively hyperoxic environment outside the womb can predispose a neonate to this condition
• [2] Anemia of prematurity (AOP) refers to a form of anemia affecting preterm infants [1] with decreased hematocrit. [2] AOP is a normochromic, normocytic hypoproliferative anemia.
• [3] May 14, 2024 — The primary cause of AOP is the impaired ability to increase serum erythropoietin (EPO) appropriately in the setting of anemia and decreased oxygen levels.

Anemia of prematurity can manifest in various ways, depending on its severity and the individual baby's condition. Here are some common signs and symptoms:

• Pale appearance: Premature babies with anemia may appear pale due to a lack of red blood cells.
• Lethargy or sluggishness: Moderate anemia can cause premature babies to be less active or lethargic.
• Poor feeding: Anemic premature babies may have difficulty feeding, which can lead to inadequate weight gain.
• Tachypnea (rapid breathing): In severe cases, anemia can cause premature babies to breathe rapidly.
• Tachycardia (fast heart rate): Anemic premature babies may also experience a fast heart rate.
• Flow murmur: A flow murmur, which is a sound heard when blood flows through the heart, can be present in severe cases of anemia.

It's essential to note that many premature babies with mild or moderate anemia may not exhibit any noticeable symptoms. However, if left untreated, anemia can lead to more serious complications.

References:

• [3] The blood that is taken is not replaced quickly, which causes anemia. The baby is born premature. Babies who are born premature (early) have lower number of red blood cells. These red blood cells also have a shorter life span when compared to the red blood cells of full term babies. This is called anemia of prematurity.
• [4] Many babies don't have symptoms. But if the red blood cells don't carry enough oxygen to the body, your baby may have trouble feeding, not gain much weight, or ...
• [7] Oct 31, 2009 — A premature baby with anaemia of prematurity will likely appear pale and lethargic. Blood work will be done to confirm a diagnosis.
• [8] Neonates are generally pale and, if anemia is severe, have tachypnea, tachycardia, and sometimes a flow murmur; hypotension is present with acute blood loss.
• [11] Your baby may have very mild symptoms of premature birth or more-serious health problems. Some signs of being born too early include: Small size, with a head that's large compared with the body. ... Premature babies are at risk of blood problems such as anemia and newborn jaundice. With anemia, the body doesn't have enough red blood cells.
• [12] This condition is also referred to as anemia of prematurity. A mechanism similar to the one that causes anemia in term infants causes anemia in preterm infants during the first 4 to 12 weeks. ... Symptoms and signs of perinatal anemia are similar regardless of the cause but vary with severity and rate of onset of the anemia. Neonates are ...
• [13] How is anemia treated? Treatment of anemia depends on the severity of the condition and baby’s symptoms or the amount of hemoglobin in the blood.

Anemia of prematurity, also known as anemia of prematurity syndrome, is a condition that affects premature infants and is characterized by low red blood cell count or hemoglobin levels.

Diagnostic Tests

The diagnosis of anemia of prematurity typically involves the following tests:

• Blood tests: A complete blood count (CBC) test measures the number of red blood cells, white blood cells, and platelets in the blood. This test can help identify low hemoglobin levels, which are a hallmark of anemia of prematurity.
• Hemoglobin level: A blood test measures the hemoglobin level in the blood. Low hemoglobin levels (typically below 10 g/dL) are indicative of anemia of prematurity [4].
• Reticulocyte count: This test measures the number of reticulocytes, which are immature red blood cells, in the blood. A low reticulocyte count can indicate a lack of production of new red blood cells, which is common in anemia of prematurity [6].
• Hematocrit (HCT) and Hemoglobin (HGB): These tests measure the concentration of red blood cells in the blood. Low HCT and HGB levels are indicative of anemia of prematurity [9].

Other Tests

In some cases, additional tests may be performed to rule out other causes of anemia or to confirm the diagnosis:

• MCV (Mean Corpuscular Volume): This test measures the average size of red blood cells. Low MCV values can indicate microcytic anemia.
• RBC transfusions: Blood tests are used to monitor the effectiveness of RBC transfusions and to determine if further transfusions are needed.

It's essential to note that a diagnosis of anemia of prematurity is typically made based on clinical symptoms, such as pale skin or mucous membranes, and confirmed with laboratory tests.

Treatment Options for Anemia of Prematurity

Anemia of prematurity can be treated with various medical interventions, including:

• Blood Transfusions: This is the primary treatment for severe anemia in premature infants. Blood transfusions help increase the red blood cell count and hemoglobin levels.
• Recombinant Erythropoietin (EPO): EPO is a hormone that stimulates the production of red blood cells. It can be administered to premature infants to help treat anemia.
• Iron Supplements: Iron supplements may be prescribed to premature infants with iron deficiency anemia.

Treatment Guidelines

According to various studies and guidelines, the following treatment approaches are recommended:

• Most healthy preterm infants have mild anemia and do not require any treatment [10].
• Premature babies who need treatment for anemia usually receive blood transfusions or EPO therapy [6][7].
• Iron supplements may be prescribed in addition to EPO therapy to prevent iron deficiency [12].

Recent Studies

A study published in 2008 found that RBC transfusion remains the primary treatment for an

The differential diagnosis of anemia of prematurity involves considering various conditions that can cause or mimic this condition. Here are some key points to consider:

• Anemia of prematurity: This is a multifactorial anemia caused by relatively low plasma erythropoietin (EPO) levels, iatrogenic blood loss, low circulating blood volumes, and insufficient erythropoiesis [15].
• Differential diagnosis: Conditions that can cause or mimic anemia of prematurity include:
  • Aplastic or hypoplastic anemia (e.g., Diamond-Blackfan)
  • Bone marrow suppression
  • Congenital dyserythropoietic anemia
  • Fanconi anemia
  • Iron deficiency anemia [5]
• Anemia of prematurity vs. other diseases: Differentiating anemia of prematurity from other diseases is crucial, as it can be caused by exposure to radiation, drugs like Benzene, chloramphenicol, alkylating agents, and viral infections [9].
• Necrotizing enterocolitis and anemia of prematurity: Necrotizing enterocolitis (NEC) is a condition that can cause anemia in preterm infants. The role of anemia of prematurity in NEC is still being researched [10].

It's essential to consider these factors when diagnosing anemia of prematurity, as they can help determine the underlying cause and guide treatment decisions.

References:

[5] Jan 16, 2024 — Diagnostic Considerations [9] Aug 19, 2024 — Anemia of prematurity is a chronic anemia generally occurring at age 4-6 weeks with a hemoglobin nadir of 7-8 g/dL (70-80 g/L) affecting preterm neonates < 32 ... [10] Semin Perinatol. 2012 Aug. 36(4):277-82. [15] Aug 24, 2020 — Differentiating Anemia of prematurity from other diseases