title: Establishment of reference intervals for complete blood count parameters during normal pregnancy in Beijing.
abstract: OBJECTIVE
  To observe the changes of complete blood count (CBC) parameters during pregnancy and establish appropriate reference intervals for healthy pregnant women.
  
  
  METHODS
  Healthy pregnant women took the blood tests at all trimesters. All blood samples were processed on Sysmex XE-2100. The following CBC parameters were analyzed: red blood cell count (RBC), hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW), platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), white blood cell count (WBC), and leukocyte differential count. Reference intervals were established using the 2.5th and 97.5th percentile of the distribution.
  
  
  RESULTS
  Complete blood count parameters showed dynamic changes during trimesters. RBC, Hb, Hct declined at trimester 1, reaching their lowest point at trimester 2, and began to rise again at trimester 3. WBC, neutrophil count (Neut), monocyte count (MONO), RDW, and PDW went up from trimester 1 to trimester 3. On the contrary, MCHC, lymphocyte count (LYMPH), PLT, and MPV gradually descended during pregnancy. There were statistical significances in all CBC parameters between pregnant women and normal women, regardless of the trimesters (P<.001). The median obtained were (normal vs pregnancy) as follows: RBC 4.50 vs 3.94×1012/L, Hb 137 vs 120 g/L, WBC 5.71 vs 9.06×109/L, LYMPH% 32.2 vs 18.0, Neut% 58.7 vs 75.0, and PLT 251 vs 202×109/L.
  
  
  CONCLUSIONS
  The changes of CBC parameters during pregnancy are described, and reference intervals for Beijing pregnant women are demonstrated in this study.
authors.affiliation: Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China.
authors.forename: Aiwei
authors.identifier: http://orcid.org/0000-0003-1079-7511
authors.initials: A
authors.lastname: Li
authors.affiliation: Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Qiao
mesh_terms: D000293:Adolescent; D000328:Adult; D000068476:Beijing / Q000453:epidemiology; D001772:Blood Cell Count / Q000592:standards*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy / Q000097:blood / Q000706:statistics & numerical data; D011250:Pregnancy Complications, Hematologic; D011295:Prenatal Care; D012016:Reference Values; D055815:Young Adult
keywords: complete blood count; pregnancy; reference interval