What Is A CBC Test & Why Is It Needed?

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A complete blood count or CBC test during pregnancy assesses the full blood count in mothers and determines any underlying diseases and conditions. Doctors may order a CBC test to look for anemia and analyze the hemoglobin and hematocrit levelsiXA blood test that calculates the percentage of red blood cells in the blood. during prenatal visits.

Although CBC tests are done in the early weeks, such as before 12 weeks of pregnancy, they are repeated a few times in the later weeks to ensure maternal wellbeing.

Read this post to learn more about CBC tests during pregnancy and how doctors interpret the results.

Why Is CBC Blood Test During Pregnancy Needed?

A CBC test usually helps your doctor get a better idea of any illnesses you may be suffering from, and may also help him diagnose fatigue, weakness, infections and other deficiency conditions such as anaemia. Infact, a CBC test is probably the first test recommended during pregnancy.

A CBC test during pregnancy is required for several reasons including:

  • Measurement of haemoglobin content.
  • Measurement of haematocrit or packed cell volume.
  • Measurement of blood plateletsiXTiny blood cells involved in the process of blood clotting. that play a role in blood clotting.
  • The amount of individual white blood cells (monocytes, lymphocytes, neutrophils, basophils and eosinophilsiXA type of white blood cells that helps fight infections. ). These numbers could prove to be helpful in the detection of any infections whatsoever.
  • The amount of red blood cells present in the blood which could helpful in the early detection of any forms of deficiency (anaemia).
CBC test during pregnancy can help detect anemia

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In some cases, your doctor may also have a blood smear test done to rule out any possible conditions such as sickle cell diseaseiXAn inherited group of blood disorders causing chronic anemia. , malaria, leukemiaiXA cancer of blood cells, hampering the body’s capacity to fight infections. and other blood diseases.

CBC test is actually one of the most simplest tests carried out during pregnancy, and is limited to merely drawing blood from the vein. There may be a small bruise at the site from where the blood is drawn, but the blood flow through the area usually stops in a couple of minutes.

Is It Really Essential During Pregnancy?

CBC test is one of the many important tests to be carried out during pregnancy. The American College of Obstetricians and Gynecologists believe that this test may also help detect anemia, after which, iron supplements can be given to improve the general health of the mother during pregnancy.

The fact that this test helps early detection of many infections and other conditions that may prove to be harmful for the baby is what makes it even more important to be carried out during pregnancy.

Other Pregnancy Tests

Apart from CBC, these are several other important tests that you may need to undergo while you are pregnant.

  • Blood type test (with Rh factor and antibody screening test)
  • Rubella titer test
  • Hepatitis BiXA severe liver damage and infection caused by the Hepatitis B virus (HBV). test
  • HIV test
  • Syphilis test
  • Glucose challenge test
  • Other tests to detect chromosomal abnormalities
  • Ultrasound
Ultrasound is a cruicial pregnancy test

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It is important to have your doctor’s opinion before undergoing any tests during this crucial period. Also make sure your doctor is aware of any medications or drugs you are already taking to rule out the risk of any complications (usually observed in individuals with bleeding disorders or those on blood thinning medications) associated with the test (1).

Frequently Asked Questions

1. How much hemoglobin is normal during pregnancy?

The normal range for hemoglobin during pregnancy ranges from 11.5 to 13.5 grams per deciliter (g/dl) (2).

2. Is 9.5 hemoglobin low during pregnancy?

Hemoglobin level below 11 g/dl is considered low during pregnancy (2).

3. How does pregnancy affect CBC?

In pregnancy, the total blood volume increases by about 1.5 liters, but the red blood cell parameters do not show significant changes. White blood cell count is found to increase while platelet count may decrease during pregnancy (usually in the third trimester) (3).

4. What is a ‘CBC with differential’ test?

A CBC test measures the total number of white cells. Whereas, a CBC with differential test reports the number of each type of these white blood cells in the blood sample (4).

A CBC test during pregnancy is one of the most basic tests, requiring simply the use of a syringe to collect blood from a vein. The test evaluates a mother’s whole blood count, which includes hemoglobin volume, hematocrit, WBCs, and RBCs, to diagnose any underlying disorders or abnormalities. It is usually done before the 12th week of pregnancy, although it can also be done any time during the pregnancy to check maternal health. If you develop a fever, exhaustion, weakness, or other symptoms during your pregnancy, your doctor may order a CBC test to determine the cause.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
  1. Tests, scans and checks – pregnancy and labour.
  2. R. Huch; (1992); The critical hemoglobin/hematocrit value in obstetrics.
  3. Surabhi Chandra et al.; (2012); Physiological Changes in Hematological Parameters During Pregnancy.
  4. Complete Blood Count (CBC).

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shreeja pillai

Shreeja holds a postgraduate degree in Chemistry and diploma in Drug Regulatory Affairs from the University of Mumbai. Before joining MomJunction, she worked as a research analyst with a leading multinational pharmaceutical company. Her interest in the field of medical research has developed her passion for writing research-based articles. As a writer, she aims at providing informative articles on health...
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