A high RDW (Red Cell Distribution Width) in pregnancy typically indicates a greater variation in the size of red blood cells. In the later stages of pregnancy, specifically the last 4-6 weeks, an unexpected rise in RDW may suggest increased bone marrow activity, though the exact stimulus for this increase remains unknown.
Here's a more detailed breakdown:
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RDW Explained: RDW measures the variation in the size of your red blood cells (anisocytosis). A normal RDW means your red blood cells are relatively uniform in size. A high RDW means there's a significant difference in the size of your red blood cells.
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High RDW Causes in General (Outside Pregnancy): Several factors can cause a high RDW, including:
- Iron deficiency anemia: The most common cause.
- Vitamin B12 deficiency
- Folate deficiency
- Hemolytic anemia
- Liver disease
- Kidney disease
- Certain hemoglobinopathies (like sickle cell anemia)
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High RDW in Pregnancy: Pregnancy itself can influence RDW levels. Several factors contribute to this:
- Physiological Anemia of Pregnancy: During pregnancy, blood volume increases significantly. While red blood cell production also increases, the plasma volume increase is proportionally larger, leading to a dilution effect and a lower hemoglobin concentration (physiological anemia). This can sometimes lead to an increased RDW.
- Nutrient Deficiencies: Pregnant women require more iron, folate, and vitamin B12. Deficiencies in these nutrients can lead to anemia with an increased RDW. It is important to take prenatal vitamins and eat a balanced diet.
- Late Pregnancy RDW Increase: As mentioned in the reference material, an unexplained RDW increase is sometimes seen in the weeks leading up to labor. This suggests increased bone marrow activity, although the cause remains unclear. This change could potentially serve as an indicator of impending labor, but more research is needed.
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Implications and Next Steps: If you have a high RDW during pregnancy, your healthcare provider will likely:
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Review your medical history and current medications.
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Order additional blood tests to determine the cause of the high RDW. These tests might include:
- Complete Blood Count (CBC) with differential
- Iron studies (serum iron, ferritin, transferrin saturation)
- Vitamin B12 and folate levels
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Recommend treatment based on the underlying cause. This might include:
- Iron supplements
- Vitamin B12 or folate supplements
- Dietary changes
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Important Note: It's crucial to discuss any abnormal lab results with your doctor. Self-treating or ignoring a high RDW can be harmful to both you and your baby. A healthcare professional can properly diagnose the cause and recommend appropriate treatment.
