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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 History

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

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