From the Research
A slightly elevated white blood cell count is normal during pregnancy, with levels ranging from 5.7 to 15.0 × 10^9/L, as shown in a recent study published in 2021 1. This physiological change is due to an increase in neutrophils, which is a normal adaptation of the maternal immune system to pregnancy. The increase in white blood cells is influenced by elevated estrogen levels and the body's response to the fetus as a foreign entity. Some key points to consider include:
- The upper reference limit for total white blood cell count is elevated by 36% in pregnancy, driven by a 55% increase in neutrophils and 38% increase in monocytes 1.
- Lymphocytes are reduced by 36% during pregnancy, while eosinophils and basophils remain unchanged 1.
- Total white blood cell count is elevated significantly further from the first day after birth, which resolves to pre-delivery levels by an average of seven days, and to pre-pregnancy levels by day 21 1.
- A more recent study published in 2024 also established comprehensive reference intervals for white blood cell counts during pregnancy, with levels ranging from 4.0 to 14.4 × 10^9/L 2. However, it is essential to note that while a slightly elevated white blood cell count can be normal during pregnancy, significantly elevated levels may indicate an underlying infection or other complications, and should be evaluated by a healthcare provider 3. In clinical practice, healthcare providers should be aware of these normal variations and interpret white blood cell counts in pregnant women with these physiological changes in mind. The use of point-of-care testing for white blood cell counting can also be beneficial in resource-limited areas or for personal health care, but traditional methods may still be necessary for accurate diagnosis 4.