From the Research
Leukocytosis is a normal finding during the third trimester of pregnancy, with white blood cell counts often reaching 10,000-15,000 cells/μL or higher due to increased neutrophil counts. This physiological change is part of the body's adaptation to pregnancy, driven by increased estrogen levels and other pregnancy-related hormones, and does not typically indicate infection or inflammation 1. The upper reference limit for total white blood cell count is elevated by 36% in pregnancy, with a reference interval of 5.7-15.0×10^9/L, primarily due to a 55% increase in neutrophils 1.
Key Points to Consider
- Physiological leukocytosis in pregnancy is mainly associated with increased neutrophil counts, especially in the third trimester 2.
- Extremely high white blood cell counts (above 20,000 cells/μL) or counts accompanied by symptoms like fever, pain, or other signs of infection should be evaluated by a healthcare provider, as they may indicate an underlying condition requiring treatment.
- Regular prenatal blood tests are essential to monitor white blood cell counts and distinguish between normal pregnancy-related changes and potential complications.
- The increase in white blood cell count is a normal response to pregnancy and resolves after delivery, with total white blood cell counts returning to pre-pregnancy levels by day 21 postpartum 1.
Clinical Implications
- Healthcare providers should be aware of the normal reference intervals for white blood cell counts in pregnant women to avoid misinterpreting physiological leukocytosis as a sign of infection or inflammation.
- Patients with symptoms suggestive of infection or other underlying conditions should be thoroughly evaluated, regardless of their white blood cell count.
- The management of leukocytosis in pregnancy should focus on identifying and treating any underlying conditions, rather than the leukocytosis itself, unless it is extremely high or accompanied by concerning symptoms.