Maternal Anemia and Pregnancy outcomes: a Systematic Review and Meta-Analysis

Authors

1 MSc Student of Epidemiology, Student Research Committee, Ilam University of Medical Sciences, Ilam, Iran.

2 Professor of Epidemiology, Public Health Faculty, Ilam University of Medical Sciences, Ilam, Iran.

3 Ph.D Candidate in Nursing, Faculty of Nursing and Midwifery, Tabriz University of Medical Sciences, Tabriz, Iran.

4 Associate Professor of Biostatistics, Psychosocial Injuries Research Center, Ilam University of Medical Sciences, Ilam, Iran.

Abstract

Background
 The aim of this study was to determine the relationship between maternal anemia during pregnancy and pregnancy outcomes.
Materials and Methods
 This systematic review was conducted in domestic (Sid, Iran.doc, Iran medex and Magiran) and international (PubMed, Science Direct, Cochrane, Medline, Web of Science, Scopus, Springer, Embase, Google scholar) databases from January 1, 1990 to April 10, 2016 with using standard key words "Pregnancy", "Pregnant women", "Hemoglobin/ haemoglobin", "Anemia/ anaemia", and "Pregnancy outcome". Relative risks (RR) and confidence intervals were extracted from each study.
Results
 Overall 30 studies with a total sample size of 1,194,746 were entered into the final meta-analysis. Maternal anemia in the first trimester showed a significant relationship with low birth weight (RR: 1.28, 95% CI, 1.10 - 1.50, P<0.01), pre-term birth (RR: 1.26, 95% CI, 1.11- 1.44, P<0.01) and small for gestational age (RR: 1.12, 95% CI, 1.05 - 1.19, P<0.01`), that means maternal anemia in the first trimester raises the risk of these outcomes.
Even though, maternal anemia in the second trimester has no significant relationship with low birth weight (RR, 1.19, 95% CI, 0.65- 2.17, P>0.05) and pre-term birth (RR: 1.35, 95% CI, 0.54 - 3.24, P>0.05). Similarly, maternal anemia in the third trimester has also, no significant relationship with low birth weight (RR: 1.23, 95% CI, 0.97 - 1.55, P>0.05) and pre-term birth (RR: 1.55, 95% CI, 0.83 - 2.88, P>0.05).
Conclusion
Maternal anemia during pregnancy in the first trimester in particular can be considered as a risk factor for pregnancy outcomes and must be treated as an advance.

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