title: Nucleated red blood cells in maternal blood during pregnancy.
abstract: OBJECTIVE
  To assess the frequencies of nucleated red blood cells (RBCs) in maternal blood during different stages of gestation and postpartum.
  
  
  METHODS
  Peripheral venous blood samples were collected longitudinally from 38 pregnant women from the first trimester to 3 months postpartum. Nucleated RBCs were isolated by using a triple-density gradient with Histopaque (Sigma Diagnostics, St. Louis, MO) and identified by Kleihauser-Betke acid stain.
  
  
  RESULTS
  The number of nucleated RBCs steadily increased from 3.9 (standard error 0.6) per 10(7) nucleated cells in early gestation (6-10 weeks) to 112.0 (standard error 7.5) per 10(7) nucleated cells near term and decreased rapidly after delivery. The number of nucleated RBCs was not related to the gender of the fetus or the ABO blood type compatibility between the mother and fetus.
  
  
  CONCLUSIONS
  The number of nucleated RBCs in the maternal blood increase progressively throughout pregnancy, with some variation from subject to subject.
authors.affiliation: Department of Obstetrics and Gynecology, National Cheng-Kung University Medical College, Tainan, Taiwan, Republic of China. paolink@mail.ncku.edu.tw
authors.forename: P L
authors.initials: PL
authors.lastname: Kuo
authors.forename: H R
authors.initials: HR
authors.lastname: Guo
mesh_terms: D000328:Adult; D004906:Erythrocyte Count; D004912:Erythrocytes / Q000473:pathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy / Q000097:blood*