What is the normal Mean Corpuscular Volume (MCV) in infants?

From the Guidelines

The normal mean corpuscular volume (MCV) in infants varies by age, with a range of 95-121 femtoliters (fL) at birth, decreasing to 70-86 fL by 6 months of age, and stabilizing at 70-90 fL by 1-2 years of age. According to the study by the Centers for Disease Control and Prevention 1, MCV is highest at birth, decreases during the first 6 months of life, then gradually increases during childhood to adult levels. Some key points to consider when evaluating MCV in infants include:

• The age-dependent variation in MCV values, with newborns having larger fetal red blood cells (macrocytes) that are gradually replaced by smaller adult-type cells during the first year of life
• The importance of using age-specific reference ranges when interpreting an infant's MCV to avoid misdiagnosis
• The potential for MCV values outside the age-appropriate range to indicate conditions such as iron deficiency, thalassemia, or vitamin B12/folate deficiency The gradual decrease in MCV reflects the normal physiologic transition from fetal to adult hematopoiesis, as noted in the study 1. It is essential to consider these factors when evaluating an infant's MCV to ensure accurate diagnosis and treatment. In clinical practice, using the most recent and highest quality evidence, such as the study by the Centers for Disease Control and Prevention 1, is crucial for making informed decisions about infant care.

From the Research

Normal MCV in Infants

• The normal mean corpuscular volume (MCV) in infants can vary depending on gestational age, with studies suggesting that MCV decreases with advancing gestational age 2.
• For instance, one study found that the MCV diminished from 119 +/- 7 fl in neonates <= 25 weeks gestation to 106 +/- 4 fl at 40 weeks 2.
• Another study found that a low MCV was more common in term infants (25%) compared with preterm infants (17.1%, P < .001) 3.
• The American College of Obstetricians and Gynecologists recommends screening for anemia with a complete blood count in the first trimester and again at 24 0/7 to 28 6/7 weeks of gestation, which can help identify infants with abnormal MCV values 4.

Factors Affecting MCV in Infants

• Iron deficiency is a common cause of anemia in pregnancy, and maternal anemia can affect the MCV of infants 4, 5, 6.
• Studies have shown that iron deficiency can progress from low iron stores to iron-deficiency anemia, and that oral iron is typically first-line therapy for treating iron deficiency anemia 5, 6.
• Other factors that can affect MCV in infants include gestational age, birth weight, and the presence of certain medical conditions, such as alpha thalassemia 3, 2.

Diagnosis and Treatment of Abnormal MCV in Infants

• Diagnosis of abnormal MCV in infants typically involves a complete blood count and may include additional tests, such as hemoglobin electrophoresis or DNA analysis 3, 2.
• Treatment of abnormal MCV in infants depends on the underlying cause, but may include iron supplementation or other therapies to address underlying medical conditions 4, 5, 6.