Prevalence of anemia in pregnant women

Determined using the Swelab Alfa Plus hematology analyzer, RBC indices were used to investigate the prevalence of anemia in pregnant women in a study from the University of Garmian, Iraq (1). In the study conducted by Rashid and coworkers, 157 pregnant women aged 17 to 49 years were included. The MCV parameter was used to classify the anemias into microcytic, normocytic, and macrocytic. The results show that the anemias in studied group of women were either microcytic or normocytic, whereas no macrocytic anemias were diagnosed.
Anemia is a serious health problem that is often affecting pregnant women. In the Iraq study, about one third of the included women were found to be anemic. The identified cases of normocytic anemia may be caused in part by the uncompensated increase in plasma volume that often occurs during pregnancy (2). However, almost 40% of the affected women were diagnosed with microcytic anemia. The most common cause of microcytic anemia is iron deficiency, which often results from inadequate nutritional intake. Rashid and coworkers emphasize the importance of dietary awareness among pregnant women. Additional tests, such as serum iron, ferritin, and transferrin levels and total iron binding capacity (TIBC) are usually determined in parallel with the CBC test to distinguish IDA from other causes of microcytic anemia, such as thalassemia.

The use of RBC indices in anemia investigations

Whereas RBC (and HCT) and HGB are used for diagnosis of anemia, the RBC indices MCV, RDW, MCH, MCHC are valuable in the morphological classification of anemia. While MCV and RDW are used to identify the type of anemia, the MCH and MCHC can be used to confirm the findings.
As an elevated HGB value is expected to correlate with an elevated RBC count, and an increase in the number of RBCs is likely to correlated with an increase in the HCT value, another useful tool to ensure that the interpretation of the RBC parameters is correct is the “rule of three”:
RBC (× 1012/L) × 3 = HGB (g/dL)
HGB (g/dL) × 3 = HCT (%).
The following steps can be used for interpretation of the RBC parameters of the CBC (4):

1. Assess HGB value relative to reference interval to determine severity of anemia.
2. Assess MCV relative to reference interval to determine class of anemia (macrocytic, normocytic, or microcytic).
3. Assess the MCHC relative to the reference interval (hypochromic or normochromic) – an increase can point to spherocytes (spherical RBCs without the central concavity).
4. Interpret the RDW relative to the reference interval (low/moderate or pronounced anisocytosis).
5. Examine the RBC morphology under the microscope and correlate findings with instrument parameters. At the same time, review for additional findings that may support diagnosis.
6. Examine RBC, HCT, MCH, and calculate the “rule of three” to ensure that the interpretations are correct.
7. Use related test results when available to verify CBC findings and for additional diagnostic information.
8. Correlate RBC parameters with WBC and PLT results for diagnostic significance.
Among factors that can affect the results from the automated cell count are lipemia or elevated WBC count (falsely elevated HGB value), blood clotting (falsely low HCT), and hemolysis (falsely elevated MCHC due to a disproportional drop in HCT versus HGB present in the plasma). The “rule of three” can be helpful to doublecheck the results if the MCHC value is within the reference interval.


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Learn more from the white paper on the clinical utility of red blood cell indices in anemia investigations.



  1. Rashid et al. Prevalence of Anemia, Iron Deficiency Anemia and its Sociodemographic Factors among Pregnant Women in Garmian Province, Kurdistan Region of Iraq. CUESJ 7, 60–66 (2023).
  2. Brill et al. Normocytic Anemia. Am Fam Physician 62, 2255–2263 (2000).
  3. White paper: Clinical utility of red blood cell indices in anemia investigations. Boule Diagnostics, 45000, Edition 1 (2023).
  4. Doig and Zhang. A Methodical Approach to Interpreting the Red Blood Cell Parameters of the Complete Blood Count. Clin Lab Sci 30, 173–185 (2017).

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