title: Anaemia in the first but not in the second or third trimester is a risk factor for low birth weight.
abstract: OBJECTIVE
  To assess pregnancy outcome in women with anaemia during pregnancy.
  
  
  METHODS
  The study design involved a retrospective chart review of all women registering for prenatal care in the area of Kuopio University Hospital between 1990 and 2000. A haemoglobin concentration below 100g/l was used as a cutoff for anaemia and affected women (N=597) were stratified by the trimester at which anaemia was diagnosed. Multiple regression analysis was used to compare obstetric outcomes in the study groups and in non-anaemic women (N=22,202).
  
  
  RESULTS
  The frequency of anaemia was 2.6%, with 0.3% occurring in the first trimester. After controlling for confounding factors, anaemia detected in the first trimester was associated with low-birth-weight infants (OR=3.14, 95% CI: 1.35-7.28) whereas the mid- and third-trimester anaemia groups showed no significantly different outcomes when compared with the non-anaemic women. First trimester anaemia was not significantly associated with small birth weight for gestational age (OR=0.98, 95% CI: 0.41-2.17) or with premature delivery <37 weeks (OR=1.80, 95% CI: 0.72-4.49).
  
  
  CONCLUSIONS
  Maternal anaemia detected in the first trimester is associated with low birth weight.
authors.affiliation: Department of Obstetrics and Gynaecology, Kuopio University Hospital, Finland.
authors.forename: Henna
authors.initials: H
authors.lastname: Hämäläinen
authors.forename: Katja
authors.initials: K
authors.lastname: Hakkarainen
authors.forename: Seppo
authors.initials: S
authors.lastname: Heinonen
mesh_terms: D000293:Adolescent; D000328:Adult; D000740:Anemia / Q000097:blood* / Q000453:epidemiology; D005260:Female; D005387:Finland / Q000453:epidemiology; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D011247:Pregnancy / Q000097:blood*; D011248:Pregnancy Complications; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First / Q000097:blood; D011262:Pregnancy Trimester, Second / Q000097:blood; D011263:Pregnancy Trimester, Third / Q000097:blood; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D006454:Hemoglobins