Is a high white blood cell (WBC) count normal during labor?

From the Guidelines

A high white blood cell (WBC) count is a normal finding during labor, with typical values ranging from 15,000-30,000 cells per microliter. This physiological response is attributed to the physical and emotional stress of labor, increased cortisol levels, and the body's inflammatory response to the process of labor [no direct evidence from 1, but general medical knowledge]. The study by Uppal et al. 1 does not directly address the normal range of WBC counts during labor, but it does mention that fever was reported in all patients who received neuraxial anaesthesia for delivery, while none had a high white cell count, except one that was attributed to the concomitant use of methylprednisolone.

Some key points to consider when evaluating WBC counts during labor include:

• The elevation in WBC count is primarily seen in neutrophils, which are the most abundant type of white blood cells
• This increase helps prepare the body for potential infections during the delivery process and assists with tissue repair afterward
• Extremely high WBC counts (above 30,000) or elevations accompanied by other concerning symptoms like fever, foul-smelling discharge, or severe pain may indicate an infection and should be evaluated by a healthcare provider
• The elevated WBC count typically returns to normal levels within 1-2 weeks after delivery as the body recovers from the birth process.

It is essential to note that the study by Uppal et al. 1 focuses on neuraxial anaesthesia and peripheral nerve blocks during the COVID-19 pandemic, and its findings may not be directly applicable to the normal range of WBC counts during labor. However, based on general medical knowledge, a high WBC count during labor is generally considered a normal physiological response, and extremely high counts or those accompanied by concerning symptoms should be evaluated by a healthcare provider.

From the Research

High WBC Count During Labor

• A high white blood cell (WBC) count during labor can be considered normal, as studies have shown that WBC counts increase significantly during pregnancy and labor 2, 3, 4.
• The upper reference limit for total WBC was elevated by 36% in pregnancy, driven by a 55% increase in neutrophils and 38% increase in monocytes 2.
• Total WBC was elevated significantly further from the first day after birth, which resolved to pre-delivery levels by an average of seven days, and to pre-pregnancy levels by day 21 2.
• The average WBC in a laboring patient was 12,450, with a range of 4,400 to 29,100, and patients with postpartum complications had a WBC similar to that of patients without complications 3.

Factors Affecting WBC Count

• Labor influenced post-cesarean WBC counts but did not obscure changes associated with infection 5.
• Multiple variables can affect post-partum leukocytosis, including age, parity, gestational age, mode of delivery, type of anesthesia, timing of cesarean delivery in relation to labor onset, and the extent of perineal trauma 4.
• The mode of delivery can also affect WBC count, with significant differences according to mode of delivery (2.34 ± 3.48,3.32 ± 3.69 and 1.60 ± 2.87 × 10^9/L for spontaneous, assisted and cesarean deliveries) 4.

Clinical Implications

• An elevated WBC obtained on admission to the labor ward is not helpful in predicting postpartum complications in mothers or newborns 3.
• Post-partum leukocytosis is a physiological phenomenon with a wide normal variation and multiple contributing factors, and as a single parameter, post-partum leukocytosis should not prompt further work up 4.
• Information gained from changes in WBC counts can be used to assess risk of infection, with a category-specific likelihood ratio for diagnosis of serious postpartum infection of 0.5,1.7, and 5.8 for different levels of percentage changes in WBC count 5.