Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2019 Aug;1450(1):47-68.
doi: 10.1111/nyas.14093. Epub 2019 Apr 17.

Maternal hemoglobin concentrations across pregnancy and maternal and child health: a systematic review and meta-analysis

Melissa F Young  1 , Brietta M Oaks  2 , Sonia Tandon  1 , Reynaldo Martorell  1 , Kathryn G Dewey  3 , Amanda S Wendt  4
Affiliations
Meta-Analysis

Maternal hemoglobin concentrations across pregnancy and maternal and child health: a systematic review and meta-analysis

Melissa F Young et al. Ann N Y Acad Sci. 2019 Aug.

Abstract

Maternal anemia is a well-recognized global health problem; however, there remain questions on specific hemoglobin (Hb) thresholds that predict health risk or protection for mother and child. We conducted a systematic review and meta-analysis to examine the associations of maternal Hb concentrations with a range of maternal and infant health outcomes, accounting for the timing of measurement (preconception, and first, second, and third trimesters), etiology of anemia, and cutoff category. The systematic review included 272 studies and the meta-analysis included 95 studies. Low maternal Hb (<110 g/L) was associated with poor birth outcomes (low birth weight, preterm birth, small-for-gestational-age (SGA), stillbirth, and perinatal and neonatal mortality) and adverse maternal outcomes (postpartum hemorrhage, preeclampsia, and blood transfusion). High maternal Hb (>130 g/L) was associated with increased odds of SGA, stillbirth, preeclampsia, and gestational diabetes. Relationships varied by the timing of measurement and cutoff category (stronger associations with lower cutoffs); limited data were available on anemia etiology. There were insufficient data for other maternal outcomes and long-term child health outcomes. Current data are insufficient for determining if revisions to current Hb cutoffs are required. Pooled high-quality individual-level data analyses, as well as prospective cohort studies, would be valuable to inform the reevaluation of Hb cutoffs.

Keywords: anemia; birth outcomes; hemoglobin; pregnancy; review.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Flow of study selection.
Figure 2
Figure 2
Meta‐analysis summary estimates of association of maternal hemoglobin concentration (g/L) measured at any point during pregnancy and LBW, PTB, and SGA by hemoglobin concentration cutoffs.
Figure 3
Figure 3
Meta‐analysis summary estimates of association of maternal hemoglobin concentration (g/L) measured at any point during pregnancy and stillbirth, perinatal mortality, and neonatal mortality by hemoglobin concentration cutoffs.
See this image and copyright information in PMC

References

    1. World Health Organization. 2015. The global prevalence of anaemia in 2011. Geneva: World Health Organization. Accessed August 28, 2017. http://apps.who.int/iris/bitstream/10665/177094/1/9789241564960_eng.pdf.
    1. Black, R.E. , Victora C.G., Walker S.P., et al 2013. Maternal and child undernutrition and overweight in low‐income and middle‐income countries. Lancet 382: 427–451. - PubMed
    1. WHO . 2009. Global health risks: mortality and burden of disease attributable to selected major risks. World Health Organization. Accessed August 28, 2017. http://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_re....
    1. WHO . 2014. Global nutrition targets 2025: anaemia policy brief (WHO/NMH/NHD/14.4). Geneva: World Health Organization.
    1. Dewey, K.G. & Oaks B.M.. 2017. U‐shaped curve for risk associated with maternal hemoglobin, iron status, or iron supplementation. Am. J. Clin. Nutr. 106(Suppl. 6): 1694s–1702s. - PMC - PubMed

Publication types