In plain words
Mean corpuscular volume, often shortened to MCV, is a number on a complete blood count. It shows how large your red blood cells are on average. Low numbers mean small cells, and high numbers mean large cells. Small cells often come with . Some people with a genetic trait called thalassemia also have small cells, even with normal iron. Your provider reads this number alongside and other results. It is not a diagnosis on its own. A provider can explain what an abnormal result means for a pregnancy and what testing comes next.
The deeper version
Mean corpuscular volume is calculated as hematocrit divided by red cell count and reported in femtoliters on automated complete blood counts. In pregnancy the reference range shifts because plasma volume expands, so anemia thresholds are set by trimester. Microcytosis with low ferritin indicates iron deficiency. Microcytosis with normal or high ferritin and a low Mentzer index (MCV divided by red cell count; Mentzer, Lancet 1973) suggests alpha- or beta-thalassemia trait, confirmed by electrophoresis and, for alpha-thalassemia, DNA testing. The WHO (2011) publishes trimester-specific hemoglobin thresholds for anemia. Partner screening is advised when trait is positive because of possible fetal implications. The controversy concerns how reliably routine indices detect trait and how to handle borderline values.
Where it comes up
- Low iron and anemiaPregnancy: Your Body
- Iron-rich foods and how to absorb themPregnancy: Eating
- Anemia and exhaustion after birthPostpartum: Your Body
- Blood-building foods after birthNourishment and Traditions
What mothers here say about mean corpuscular volume
No one has posted under this term yet.
Sources
- World Health Organization — Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity (2011)
- Mentzer WC Jr. — Differentiation of iron deficiency from thalassemia trait, The Lancet (1973)