Anaemia in Pregnancy across Tanzania: A Comprehensive Review of Prevalence, Risk Factors, and Birth Outcomes

Background Anaemia during pregnancy is a major public health challenge globally, particularly in low- and middle-income countries like Tanzania. It is linked to adverse maternal and neonatal outcomes. Although several studies have been conducted across different regions in Tanzania, a comprehensive synthesis is needed to inform targeted interventions. This study aimed to assess the prevalence of anaemia, its associated factors, and perinatal outcomes among pregnant women in Tanzania. Methods A systematic search was conducted across PubMed, Google Scholar, AJOL, and Scopus for observational studies published between 2010 and 2025 on anaemia among pregnant women in Tanzania. Eligible studies reported on prevalence and/or associated factors. Two reviewers independently screened, extracted data, and assessed study quality using PRISMA guidelines and the Modified Newcastle-Ottawa Scale. A narrative synthesis was used to thematically group and interpret the findings. Results Twelve studies met the inclusion criteria, with anaemia prevalence ranging from 20–83.5%, with a pooled estimate of 52.4% (95% CI: 43.1–61.6%). A total of 14 risk factors were identified, including low income, limited education, poor dietary habits, younger age, short pregnancy intervals, multigravidity, advanced gestational age, and infections such as malaria and HIV. In contrast, nine protective factors were reported, such as higher education, food security, adequate knowledge and positive attitudes, employment, optimal ANC attendance, and living closer to health facilities. Anaemia was significantly associated with low birth weight and preterm birth. Conclusion Anaemia in pregnancy remains prevalent in Tanzania and is driven by socioeconomic, nutritional, reproductive, and health-related factors. Targeted interventions focusing on improving maternal nutrition, education, and ANC utilization are essential to reduce anaemia and its impact on pregnancy outcomes.