Dataset Information

White blood cells in pregnancy: reference intervals for before and after delivery.

ABSTRACT:

Background

White blood cells (WBC) are commonly measured to investigate suspected infection and inflammation in pregnant women, but the pregnancy-specific reference interval is variably reported, increasing diagnostic uncertainty in this high-risk population. It is essential that clinicians can interpret WBC results in the context of normal pregnant physiology, given the huge global burden of infection on maternal mortality.

Methods

We performed a longitudinal, repeated measures population study of 24,318 pregnant women in Oxford, UK, to map the trajectory of WBC between 8-40 weeks of gestation. We defined 95% reference intervals (RI) for total WBC, neutrophils, lymphocytes, eosinophils, basophils, and monocytes for the antenatal and postnatal periods.

Findings

WBC were measured 80,637 times over five years. The upper reference limit for total WBC was elevated by 36% in pregnancy (RI 5.7-15.0×10⁹/L), driven by a 55% increase in neutrophils (3.7-11.6×10⁹/L) and 38% increase in monocytes (0.3-1.1×10⁹/L), which remained stable between 8-40 weeks. Lymphocytes were reduced by 36% (1.0-2.9×10⁹/L), while eosinophils and basophils were unchanged. Total WBC was elevated significantly further from the first day after birth (similar regardless of the mode of delivery), which resolved to pre-delivery levels by an average of seven days, and to pre-pregnancy levels by day 21.

Interpretation

There are marked changes in WBC in pregnancy, with substantial differences between cell subtypes. WBC are measured frequently in pregnant women in obstetric and non-obstetric settings, and results should be interpreted using a pregnancy-specific RI until delivery, and between days 7-21 after childbirth.

Funding

None.

SUBMITTER: Dockree S

PROVIDER: S-EPMC8626574 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundPregnancy has major effects that make hematology parameters outside of normal reference ranges. Therefore, we conducted this study to establish reference intervals for Vietnamese pregnant women.MethodsFrom June 2023 to Augst 2023, blood samples from 879 eligible pregnant women were run on DxH 900 hematology analyzer and ACL TOP 550 coagulation analyzer. The tested parameters are prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), white blood cell (WBC) and its differentials (neutrophils, lymphocytes, monocytes, eosinophils and basophils), red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), RBC distribution width (RDW), RBC distribution width standard deviation (RDW-SD), platelet count (PLT), mean platelet volume (MPV). A non-parametric method was used to establish the 2.5th and 97.5th percentile reference intervals.ResultsPT, APTT decrease but fibrinogen increases during pregnancy. Physiological adaptations of pregnancy result in a decrease in RBC count, but an increase in WBC count and no changes in platelet count. The reference intervals for PT (seconds), APTT (seconds), fibrinogen (mg/dL), in the first trimester were 10.30-12.88, 25.40-35.46, 280.28-559.00, in the second trimester were 9.80-11.66, 24.05-33.23, 347.75-593.35, in the third trimester were 9.60-11.40, 23.40-31.80, 330.28-628.56, respectively. The reference intervals for main hematology parameters which are WBC (× 109/L), RBC (× 1012/L), HGB (g/dL), HCT (%), PLT (× 109/L) in the first trimester were 6.33-15.24, 3.73-5.32, 10.33-13.95, 32.22-42.29, 169.66-413.88, in the second trimester were 6.99-15.55, 3.33-4.98, 9.71-13.17, 30.26-40.07, 172.34-372.19, in the third trimester were 6.22-14.14, 3.54-4.98, 9.80-13.97, 31.11-42.70, 151.30-417.14, respectively.ConclusionsMost established referenced intervals from each trimester differ from other trimesters. These trimester-specific reference ranges for Vietnamese pregnant women will aid clinicians in entepreting parameters and help other laboratories adopt these ranges after validating.Trial registrationThis study is registered at www.Clinicaltrialsgov as NCT05929326.