title: Low first-trimester hemoglobin and low birth weight, preterm birth and small for gestational age newborns.
abstract: OBJECTIVE
  To examine the relationship between first-trimester hemoglobin (Hb) concentration and risk of low birth weight (LBW), preterm birth and small for gestational age (SGA).
  
  
  METHODS
  Data were obtained from a population-based prenatal care program in China. A total of 88,149 women who delivered during 1995-2000 and had their Hb measured in the first trimester were selected as study subjects.
  
  
  RESULTS
  The prevalence of anemia (Hb<110 g/L) was 22.1% in the first trimester. The risk of LBW, preterm birth and SGA was increased steadily with the decrease of first-trimester Hb concentration. After controlling for confounding factors, women with Hb 80-99 g/L had significantly higher risk for LBW (OR=1.44, 95% CI 1.17-1.78), preterm birth (OR=1.34, 95% CI 1.16-1.55) and SGA (OR=1.13, 95% CI 0.98-1.31) than women with Hb 100-119 g/L. No elevated risk was noted for women with Hb> or =120 g/L.
  
  
  CONCLUSIONS
  Low first-trimester Hb concentration increases the risk of LBW, preterm birth and SGA.
authors.affiliation: Institute of Reproductive and Child Health, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100083, China. renag@sohu.com
authors.forename: A
authors.initials: A
authors.lastname: Ren
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: R W
authors.initials: RW
authors.lastname: Ye
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: J M
authors.initials: JM
authors.lastname: Liu
authors.forename: Z
authors.initials: Z
authors.lastname: Li
mesh_terms: D000328:Adult; D000740:Anemia / Q000150:complications*; D016022:Case-Control Studies; D002681:China; D015331:Cohort Studies; D005260:Female; D006454:Hemoglobins / Q000032:analysis* / Q000172:deficiency; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D016017:Odds Ratio; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic; D011261:Pregnancy Trimester, First; D047928:Premature Birth / Q000097:blood* / Q000453:epidemiology; D012307:Risk Factors
chemical_list: D006454:Hemoglobins