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Am J Perinatol 2000; Volume 17(Number 03): 137-146
DOI: 10.1055/s-2000-9508
Copyright © 2000 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662

ANEMIA DURING PREGNANCY AND BIRTH OUTCOME: A META-ANALYSIS

Xu Xiong1,4 , Pierre Buekens2 , Sophie Alexander3 , Nestor Demianczuk1 , Elisabeth Wollast3
  • 1Perinatal Research Center and the Department of Obstetrics & Gynecology, University of Alberta, Canada
  • 2 Department of Maternal and Child Health, School of Public Health, University of North Carolina at Chapel Hill
  • 3Department of Epidemiology and Social Medicine, School of Public Health, Universite Libre de Bruxelles, Belgium
  • 4At time of study, Dr. Xu Xiong was with the Department of Epidemiology and Social Medicine, School of Public Health, Universite Libre de Bruxelles, Belgium
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Publication Date:
31 December 2000 (online)

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ABSTRACT

To determine the relationship between maternal anemia [hemoglobin (Hgb) < 10-11 g/dL] and various birth outcomes, a meta-analysis was conducted based on published literature identified by MEDLINE and manual search from 1966 through 1999. Odds ratios (OR) from selected studies were pooled according to the gestational age at anemia diagnosis. The meta-analysis shows that maternal anemia during early pregnancy was associated with slightly increased preterm birth [pooled adjusted OR (aOR): 1.32, 95% confidence interval (CI): 1.01-1.74], and nonstatistically significant increased low birth weight [pooled aOR: 1.39 (0.70-2.74)], and was not associated with fetal growth restriction [pooled aOR: 1.01 (0.73-1.38)]. However, there was a nonstatistically significant inverse relationship between anemia during late pregnancy and preterm birth [pooled aOR: 0.92 (0.54-1.84)] and low birth weight [pooled aOR: 0.80 (0.64-1.00)]. Anemia was not statistically significantly associated with hypertensive disorders of pregnancy regardless of stage of pregnancy [pooled OR: 0.80 (0.53-1.20)]. The relationship between anemia and perinatal mortality was inconclusive. A few studies indicated that severe maternal anemia (Hgb < 8-8.5 g/dL) was associated with increased risk of poor outcomes. We conclude that early pregnancy anemia is associated with slightly increased risk of preterm birth. The trend toward an inverse association of anemia determined during late pregnancy with preterm birth and low birth weight may reflect the benefit of plasma volume expansion.

KEYWORD

Anemia - fetal growth restriction - low birth weight - meta-analysis - perinatal mortality - preterm birth

REFERENCES

  • 1 DeMaeyer E, Tegman M A. The prevalence of anemia in the world.  World Health Stat Q . 1985;  38 302-316
    PubMedGoogle Scholar
  • 2 Lieberman E, Ryan K J, Monson R R, Schoenbaum S C. Association of maternal hematocrit with premature labor.  Am J Obstet Gynecol . 1988;  159 107-114
    PubMedGoogle Scholar
  • 3 Klebanoff M A, Shiono P H, Berendes H W, Rhoads G G. Facts and artifacts about anemia and preterm delivery.  JAMA . 1989;  262 511-515
    CrossrefPubMedGoogle Scholar
  • 4 Lu Z M, Goldenberg R L, Cliver S P, Cutter G, Blankson M. The relationship between maternal hematocrit and pregnancy outcome.  Obstet Gynecol . 1991;  77 190-194
    CrossrefPubMedGoogle Scholar
  • 5 Scholl T O, Hediger M L, Fischer R L, Shearer J W. Anemia vs iron deficiency: increased risk of preterm delivery in a prospective study.  Am J Clin Nutr . 1992;  55 985-988
    CrossrefPubMedGoogle Scholar
  • 6 Scholl T O, Hediger M L. Anemia and iron-deficiency anemia: compilation of data on pregnancy outcome.  Am J Clin Nutr . 1994;  59(suppl) 492S-501S
    PubMedGoogle Scholar
  • 7 Lister U G, Rossiter C E, Chong H. Perinatal Mortality.  Br J Obstet Gynecol . 1985;  5(suppl) 86-97
    PubMedGoogle Scholar
  • 8 Murphy J F, O'Riordan J, Newcombe R G, Coles E C, Pearson J F. Relation of haemoglobin levels in the first and second trimesters to outcome of pregnancy.  Lancet . 1986;  I 992-994
    PubMedGoogle Scholar
  • 9 Knottnerus J A, Delgado L, Knipschild P G, Essed G G, Smits F. Maternal haemoglobin and pregnancy outcome.  Lancet . 1986;  ii 282
    PubMedGoogle Scholar
  • 10 Lieberman E, Ryan K J, Monson R R, Schoenbaum S C. Risk factors accounting for racial differences in the rate of premature birth.  N Engl J Med . 1987;  317 743-748
    CrossrefPubMedGoogle Scholar
  • 11 Knottnerus J A, Delgado L, Knipschild P G, Essed G G, Smits F. Haematologic parameters and pregnancy outcome.  J Clin Epidemiol . 1990;  43 461-466
    CrossrefPubMedGoogle Scholar
  • 12 Klebanoff M A, Shiono P H, Selby J V, Trachtenberg A I, Graubard B I. Anemia and spontaneous preterm birth.  Am J Obstet Gynecol . 1991;  164 59-63
    CrossrefPubMedGoogle Scholar
  • 13 Meis P J, Michielutte R, Peters T J. Factors associated with preterm birth in Cardiff, Wales. II. Indicated and spontaneous preterm birth.  Am J Obstet Gynecol . 1995;  173 597-602
    CrossrefPubMedGoogle Scholar
  • 14 Xiong X. Anemia during pregnancy and birth outcome: new data from China & a meta-analysis.  Doctoral Thesis. Brussels, Belgium: Universite Libre de Bruxelles Health Science Library; 1996
    Google Scholar
  • 15 Xiong X, Buekens P, Alexander S, Wollast E. The relationship between anemia during pregnancy and birth outcome.  Arch Public Health . 1996;  53(suppl) 136
    PubMedGoogle Scholar
  • 16 Zhou L M, Tang W W, Hua J Z, Deng C Q, Tao X, Stoltzfus R J. Relation of hemoglobin measured at different times in pregnancy to preterm birth and low birth weight in Shanghai, China.  Am J Epidemiol . 1998;  148 998-1006
    PubMedGoogle Scholar
  • 17 Siega-Riz A M, Adair L S, Hobel C J. Maternal hematologic changes during pregnancy and effect of iron status on preterm delivery in a west Los Angeles population.  Am J Perinatal. 1998;  15 515-522
    PubMedGoogle Scholar
  • 18 World Health Organization. Nutritional anaemias: report of a WHO scientific group. Geneva, Switzerland: World Health Organization; 1968 Technical Report Series, No. 405
    Google Scholar
  • 19 Cunningham F G, McDonald P C, Gant N F. Williams Obstetrics, 18th ed. Norwalk, Connecticut: Appleton and Lange; . 1989: 779-780
    Google Scholar
  • 20 Centers for Disease Control. CDC criteria for anemia in children and childbearing aged women.  MMWR Morb Mortal Wkly Rep  1989;  38 400-404
    PubMedGoogle Scholar
  • 21 Mahomed K. Routine iron supplementation in pregnancy. In: Enkin MW, Keirse MJNC, Renfrew MJ, Neilson JP, eds. Pregnancy and Childbirth Module, ``Cochrane Database of Systematic Reviews'': Review No 03157, April 28, 1993. Published through ``Cochrane Update on Disk,'' Oxford: Update Software; 1997
    Google Scholar
  • 22 Petitti D B. Meta-analysis, Decision Analysis and Cost-effectiveness Analysis. New York: Oxford University Press; 1994;14-20,70-129
    Google Scholar
  • 23 Rothman K J, Greenland S. Modern Epidemiology.  Philadelphia: Lippincott-Raven 1998: 643-673
    Google Scholar
  • 24 Dersimonian R, Laird N. Meta-analysis in clinical trials.  Controlled Clinical Trials . 1986;  7 177-188
    CrossrefPubMedGoogle Scholar
  • 25 Xiong X, Buekens P, Wollast E. IUD use and the risk of ectopic pregnancy: a meta-analysis of case-control studies.  Contraception . 1995;  52 23-34
    CrossrefPubMedGoogle Scholar
  • 26 Chesley L C. Plasma and red cell volume during pregnancy.  Am J Obstet Gynecol . 1972;  112 440-450
    PubMedGoogle Scholar
  • 27 Hytten F E. Blood volume changes in normal pregnancy.  Clin Haematol . 1985;  14 601
    PubMedGoogle Scholar
  • 28 Institute of Medicine Nutrition during pregnancy. Part II: Nutrient Supplements. Washington, DC: National Academy Press 1990: 272-298
    Google Scholar
  • 29 Higgins A C, Pencharz P B, Strawbrige J E, Maughan G B, Moxeley J E. Maternal haemoglobin change and their relationship to infant birth weight in mothers receiving a program of nutritional assessment and rehabilitation.  Nutr Res . 1982;  2 641-649
    PubMedGoogle Scholar
  • 30 Gibson H M. Plasma volume and glomerular filtration rate in pregnancy and their relationship to differences in fetal weight.  J Obstet Gynaecol Brit Commonw . 1973;  80 1067-1074
    PubMedGoogle Scholar
  • 31 Koller O, Sagen N, Ulstein M, Vaula D. Fetal growth restriction associated with inadequate hemodilution in otherwise uncomplicated pregnancy.  Acta Obstet Gynecol Scand . 1979;  58 9-13
    PubMedGoogle Scholar
  • 32 Goodlin R C, Dobry C A, Anderson J C, Woods R E, Quaife M. Clinical signs of normal plasma volume expansion during pregnancy.  Am J Obstet Gynecol . 1983;  145 1001-1009
    PubMedGoogle Scholar
  • 33 Koller O, Sandvei R, Sagen N. High hemoglobin levels during pregnancy and fetal risk.  Int J Gynaecol Obstet . 1980;  18 53-56
    PubMedGoogle Scholar
  • 34 Peto R. Discussion of Peto R. Why do we need systematic overview of randomized trials?.  Stat Med . 1987;  6 242
    PubMedGoogle Scholar
  • 35 Canner P I, Huang Y B, Meinert C L. On the detection of outliers in medical and surgical trials. I. Practical consideration.  Control Clin Trials . 1981;  2 231-240
    PubMedGoogle Scholar
  • 36 Reinhardt M C. Maternal anaemia in Abidjan-Its influence on placenta and newborns.  Helv Paediat Acta . 1978;  33(suppl) 43-63
    PubMedGoogle Scholar
  • 37 Steer P, Alam M A, Wadsworth J, Welch A. Relation between maternal haemoglobin concentration and birth weight in different ethnic groups.  BMJ . 1995;  310 489-491
    CrossrefPubMedGoogle Scholar
  • 38 Bhargava M, Kumar R, Lyer P U, Ramji S, Kapani V, Bhargava S K. Effect of maternal anaemia and iron depletion on foetal iron stores, birthweight and gestation.  Acta Padiatr Scand . 1989;  78 321-322
    PubMedGoogle Scholar
  • 39 Duthie S J, King P A, To W K, Lopes A, Ma H K. A case controlled study of pregnancy complicated by severe maternal anaemia.  Aust NZ J Obstet Gynecol . 1991;  31 125-127
    PubMedGoogle Scholar