What is the management of leukocytosis (elevated white blood cell count) during pregnancy?

Management of Leukocytosis During Pregnancy

Elevated white blood cell (WBC) count during pregnancy is often physiological and typically does not require specific treatment unless it is associated with an underlying pathological condition.

Normal Physiological Changes in WBC During Pregnancy

• Pregnancy naturally causes an increase in WBC count, with reference intervals significantly higher than non-pregnant values 1, 2:

  • Pre-pregnancy/early pregnancy (≤2 weeks): 4.0-10.0 × 10^9/L
  • Early pregnancy (3-5 weeks): 4.7-11.9 × 10^9/L
  • Established pregnancy (≥6 weeks): 5.7-14.4 × 10^9/L 2

• The upper reference limit for WBC is elevated by approximately 36% during pregnancy (5.7-15.0 × 10^9/L), primarily driven by 1:

  • 55% increase in neutrophils (3.7-11.6 × 10^9/L)
  • 38% increase in monocytes (0.3-1.1 × 10^9/L)
  • 36% reduction in lymphocytes (1.0-2.9 × 10^9/L)

• WBC counts typically increase from the 1st to 3rd trimester and peak in the immediate postpartum period 3

Evaluation of Leukocytosis During Pregnancy

1. Use pregnancy-specific reference ranges when interpreting WBC counts 4

2. Obtain a complete blood count with differential to determine:

   • Types and maturity of white blood cells
   • Uniformity of white blood cells
   • Presence of toxic granulations 4

3. Rule out pathological causes of leukocytosis:

   • Infections (particularly bacterial)
   • Leukemia or other hematologic malignancies
   • Medications (corticosteroids, epinephrine)
   • Stress (surgery, trauma)
   • Chronic inflammatory conditions 4

4. Consider physiological causes:

   • Normal pregnancy-induced leukocytosis
   • Labor and delivery (further increases WBC)
   • Emotional stress 4, 5

Management Algorithm

1. For asymptomatic pregnant women with WBC <15.0 × 10^9/L:

   • Routine prenatal care
   • No specific intervention needed
   • Consider repeating CBC if clinically indicated 1, 2

2. For WBC >15.0 × 10^9/L without symptoms:

   • Repeat CBC with differential
   • Monitor for signs of infection or other pathology
   • Consider more frequent monitoring 5

3. For elevated WBC with symptoms (fever, pain, etc.):

   • Complete evaluation for infection or other pathology
   • Treat underlying cause if identified
   • Consider consultation with maternal-fetal medicine and/or hematology if cause unclear 6

4. For very high WBC (>20.0 × 10^9/L) or symptoms of leukostasis:

   • Urgent evaluation for hematologic malignancy
   • Consider leukapheresis for symptomatic leukostasis (hypoxia, neurological symptoms, renal failure, cardiac ischemia)
   • Initiate prompt treatment, such as steroid prephase if ALL is suspected 6

5. For leukocytosis with high risk of tumor lysis syndrome (WBC >100 × 10^9/L):

   • Increased hydration (3 L/m² per day)
   • Rasburicase prophylaxis
   • Monitor for electrolyte abnormalities 6

Special Considerations

• Postpartum period: WBC counts typically remain elevated for approximately 7 days after delivery and return to pre-pregnancy levels by day 21 1

• Chronic myeloid leukemia (CML) diagnosed during pregnancy:

  • First-line treatment is typically a short course of hydroxyurea for symptomatic patients with high WBC counts 6
  • Tyrosine kinase inhibitors (TKIs) should be avoided during pregnancy due to teratogenicity risk 6

• Acute lymphoblastic leukemia (ALL) during pregnancy:

  • Management depends on trimester and requires close collaboration with obstetric and fetal medicine teams
  • First trimester: Consider pregnancy termination as standard ALL therapy poses significant fetal risk
  • Later trimesters: Many chemotherapy agents can be safely administered, but systemic antifolates should be avoided 6

Monitoring and Follow-up

• Monitor WBC counts periodically throughout pregnancy, with increased frequency if values are abnormal or trending upward

• Remember that WBC counts naturally increase further during labor and immediately postpartum 1, 3

• Postpartum leukocytosis typically resolves within 7 days after delivery 1

Important Caveats

• Pregnancy-induced leukocytosis can mask infections or hematologic disorders

• Avoid unnecessary antibiotic treatment for asymptomatic leukocytosis that is likely physiological 5

• Extremely high WBC counts (>20 × 10^9/L) persisting for extended periods during pregnancy are rare and warrant thorough investigation 5