What is the management approach for a raised white blood cell (WBC) count in pregnancy?

Management of Raised White Blood Cell Count in Pregnancy

Initial Assessment

A raised WBC count in pregnancy requires immediate evaluation for infection and sepsis, as this represents the most critical and treatable cause affecting maternal and fetal outcomes.

Establish Pregnancy-Specific Context

• Normal WBC ranges are substantially elevated in pregnancy: the upper reference limit increases by 36% (5.7-15.0 × 10⁹/L) compared to non-pregnant women, driven primarily by a 55% increase in neutrophils (3.7-11.6 × 10⁹/L) 1
• Gestational age matters: WBC rises rapidly before 7 weeks, then plateaus at 5.7-14.4 × 10⁹/L for ≥6 weeks gestation 2
• Labor causes dramatic elevation: WBC during active labor averages 15.3 × 10⁹/L (range 5.3-25.3 × 10⁹/L), with values up to 33.5 × 10⁹/L documented in healthy laboring women without sepsis 3
• Postpartum spike is expected: WBC increases further on day 1 postpartum regardless of delivery mode, normalizing by day 7-21 1

Immediate Red Flags Requiring Urgent Action

If any of the following are present, initiate sepsis protocol immediately:

• Fever: temperature >38°C (100.4°F) or <36°C (96.8°F) 4
• Severe leukopenia: WBC <5,000/µL with lymphopenia indicates severe infection with high mortality risk 4
• Symptomatic infection: dysuria, respiratory symptoms, wound infection, or altered mental status 4
• Lactate elevation: >2 mmol/L outside of labor 4
• Hypotension: SBP <90 mmHg or MAP <65 mmHg after fluid resuscitation defines septic shock 4
• Organ dysfunction: platelets <100 × 10⁹/L, creatinine >1.2 mg/dL, bilirubin >2 mg/dL, or new respiratory failure 4

Diagnostic Algorithm for Elevated WBC

Step 1: Obtain Complete Blood Count with Differential

• Assess neutrophil percentage and band forms to evaluate for left shift 4
• Left shift criteria: band neutrophils ≥6% or absolute band count ≥1,500/mm³ has a likelihood ratio of 14.5 for bacterial infection 4
• Evaluate other cell lines: eosinophilia suggests parasitic/allergic conditions; lymphocytosis may indicate viral illness 5

Step 2: Blood Cultures Before Antibiotics

• Obtain blood cultures immediately if sepsis is suspected before administering any antibiotics 4
• Do not delay antibiotics while awaiting culture results if sepsis criteria are met 4

Step 3: Assess for Non-Infectious Causes

Consider benign physiologic causes only after excluding infection:

• Stress-induced leukocytosis: surgery, exercise, trauma, emotional stress can double WBC within hours 5
• Medications: certain drugs cause leukocytosis 5
• Chronic conditions: obesity, smoking, chronic inflammatory conditions 5
• Pregnancy-induced leukocytosis: rare cases with WBC >20 × 10⁹/L lasting weeks have been reported, resolving after delivery 6

Step 4: Evaluate for Hematologic Malignancy

Refer to hematology/oncology if:

• Constitutional symptoms present: fever, weight loss, bruising, fatigue 5
• Malignancy cannot be excluded or no other likely cause identified 5
• Confirmed chronic myeloid leukemia: leukapheresis can temporize rising WBC, though no specific threshold is established 4

Management Protocol

For Sepsis or Suspected Bacterial Infection

Initiate empiric antibiotics immediately after obtaining cultures:

• Ampicillin 100-150 mg/kg/day IV divided every 8-12 hours 4
• Plus gentamicin or cefotaxime for gram-negative coverage 4
• ICU admission required for septic shock (persistent hypotension after fluids) 4

For Asymptomatic Elevation

• Monitor closely if WBC is within pregnancy-specific reference ranges and patient is asymptomatic 1, 2
• Repeat CBC with peripheral smear to assess cell morphology, maturity, and toxic granulations 5
• Increase surveillance frequency if WBC trends upward or approaches upper limits 2

Special Peripartum Considerations

• Expect WBC elevation during labor: values up to 25 × 10⁹/L are normal 3
• Postpartum spike is physiologic: further elevation on day 1 postpartum resolves by day 7-21 1
• Do not attribute fever to "normal postpartum leukocytosis": fever always requires infection workup regardless of WBC 4

Critical Pitfalls to Avoid

• Never dismiss fever because "WBC is always high in pregnancy": fever with leukocytosis mandates sepsis evaluation 4
• Do not use non-pregnant reference ranges: this leads to false reassurance when WBC is actually pathologically elevated 1, 2
• Severe leukopenia is more concerning than leukocytosis: WBC <5,000/µL indicates severe infection with high mortality 4
• Do not delay antibiotics for culture results: obtain cultures first, then treat immediately if sepsis suspected 4
• Pregnancy-induced leukocytosis is a diagnosis of exclusion: infection must be ruled out first 6