title: Hemoconcentration in smoking mothers is associated with impaired fetal growth.
abstract: OBJECTIVE
  To examine the effect of maternal smoking on the relationship between maternal hemoglobin levels and pregnancy outcome.
  
  
  METHODS
  A prospective study of healthy parous women from early pregnancy and of their infants.
  
  
  METHODS
  Three Scandinavian university hospitals covering all deliveries from well defined geographical areas.
  
  
  METHODS
  Smoking (669) and non-smoking (368) mothers, para 1 and 2 and with > or = 37 weeks of gestational length.
  
  
  METHODS
  Birth weight and placental weight. Ponderal Index and Placental Index as measures of possible discordant fetal and placental growth.
  
  
  RESULTS
  In non-smoking mothers the hemoglobin levels in the three trimesters had no relation to birth weight. In smoking mothers a significantly lower birth weight was seen with a high hemoglobin level in the third trimester, but hemoglobin levels in early or mid-pregnancy had no association to birth weight. Smoking mothers also had a significantly greater fall in hemoglobin concentration from first to second and third trimester as compared to non-smokers although ferritin levels were similar in smokers and non-smokers, implying similar iron stores. The ratio of placental weight to the weight of the newborn was significantly higher in smokers, but no association was found to different hemoglobin levels.
  
  
  CONCLUSIONS
  Fetal growth impairment associated with maternal smoking is even more pronounced in smoking mothers with high hemoglobin levels in late pregnancy. Smoking mothers were also found to have disproportional fetal/placental growth with relatively high placental weights. In non-smoking mothers hemoglobin levels had no relation to birthweight.
authors.affiliation: Department of Obstetrics & Gynecology, University Hospital, Uppsala, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Zarén
authors.forename: G
authors.initials: G
authors.lastname: Lindmark
authors.forename: P
authors.initials: P
authors.lastname: Bergsjø
mesh_terms: D000328:Adult; D001034:Apgar Score; D001724:Birth Weight / Q000187:drug effects; D005314:Embryonic and Fetal Development / Q000187:drug effects; D005260:Female; D005293:Ferritins / Q000032:analysis; D005317:Fetal Growth Retardation; D006128:Growth / Q000187:drug effects; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000139:chemically induced*; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012907:Smoking / Q000009:adverse effects*
chemical_list: D006454:Hemoglobins; D005293:Ferritins