Information about a laboratory test

Hematocrit (HCT) in Pregnancy: How Are Results Interpreted?

Physiologic changes in blood volume during pregnancy can affect hematocrit, so a single non-pregnant adult reference range may not fully reflect pregnancy context.

Test summary

Test name
Hematocrit (HCT)
Abbreviations
HCT, Hct
Category
Hematology
Panel
Complete Blood Count (CBC) / Hemogram
Specimen
Whole blood
Common units
%, L/L

What does the test measure?

Shows the percentage of blood volume that is made up of red blood cells.

Why is the test ordered?

Helps evaluate anemia, increased red-cell mass, and changes related to fluid status as part of the complete blood count.

Information about a low result

Low hematocrit may occur with anemia and can be associated with blood loss, reduced red blood cell production, or increased red blood cell destruction.

Information about a high result

High hematocrit may occur with dehydration or conditions that increase red blood cell mass; the result alone does not identify the cause.

Reference and clinical context

Use the reference interval printed on your own laboratory report first. Reference intervals may vary by laboratory, method, unit, age, sex, pregnancy, specimen, and other conditions. Numeric records in this workbook are explicitly labeled as either source-based example reference intervals or clinical decision cutoffs.

Reference range 1

>= 40 – <= 55 %

Population
Adults
Sex
Male
Specimen
Whole blood

Example reference interval

MedlinePlus example. Laboratory-specific ranges may differ.

Reference range 2

>= 36 – <= 48 %

Population
Adults
Sex
Female
Specimen
Whole blood

Example reference interval

MedlinePlus example. Laboratory-specific ranges may differ.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

During pregnancy, hematocrit is usually interpreted together with hemoglobin and tests of iron status. When supported by a source, trimester-specific reference intervals should be stored as separate records.

Related specialties

  • Hematology
  • Internal Medicine
  • Pediatrics
  • Obstetrics and Gynecology

Frequently asked questions

Sources

  1. CBC blood test — U.S. National Library of Medicine (MedlinePlus)

    Government medical reference · 2024 · CBC components; example adult reference ranges; high/low RBC, WBC and platelet context · Verified: Aug 11, 2026

  2. Hematocrit Test — U.S. National Library of Medicine (MedlinePlus)

    Government medical reference · 2024 · Hematocrit purpose and interpretation · Verified: Aug 11, 2026

  3. Guideline on haemoglobin cutoffs to define anaemia in individuals and populations — World Health Organization

    WHO guideline · 2024 · Age-, sex- and pregnancy-specific clinical haemoglobin cutoffs; not laboratory reference intervals · Verified: Aug 11, 2026