Association between anemia in pregnancy with low birth weight and preterm birth in Ethiopia: A systematic review and meta-analysis

Background Anemia in pregnancy has been associated with a number of adverse birth outcomes, such as low birth weight (LBW) or preterm birth (PTB). However, the evidence from primary studies on anemia in pregnancy with LBW and PTB is contentious. Moreover, a systematic review and meta-analysis to summarize these findings have not been conducted for Ethiopia. This study aimed to synthesize the best available evidence and quantify the strength and direction of the association of anemia in Ethiopia. Methods This review examined women with singleton pregnancies with low birth weight (LBW) and preterm birth (PTB). We retrieved studies from PubMed, Wiley, Cochrane databases, and Google Scholar from inception to February 2, 2024. The World Health Organization (WHO) defines anemia in pregnancy as a low blood haemoglobin (Hgb) concentration below 11 g/dl or a hematocrit level of < 33%. When the newborn's weight was below 2500 g, LBW was considered. Preterm birth refers to the birth of a baby before 37 completed weeks of gestation. Meta-analysis was conducted using fixed and random effects models. The degree of heterogeneity, publication bias, and quality of the evidence of studies was assessed. Results There were 35 and 8 studies, with 14,319 and 3,265 respondents included in the meta-analysis for LBW and PTB, respectively. Neonates born to women who had normal Hgb levels were less likely to be LBW [pooled odds ratio (POR) = 0.22, 95% CI: (0.17, 0.28); I-2 = 80%] (low-quality evidence). Neonates born to women with normal Hgb levels had a lower risk of PTB [POR = 0.22, 95% CI: 0.18, 0.28; I-2 = 19%] (very low-quality evidence). The effect size estimate remained significant after sub-group analysis based on study design and province, except in two retrospective cohort studies for LBW. Conclusion The findings suggest major implications for strengthening the implementation of nutrition policies to prevent anemia during pregnancy in Ethiopia. Further research is warranted to assess interventions that are effective in combating maternal anemia to reduce rates of LBW and PTB.