Pregnant women are among the population groups most vulnerable to the development of anemia, as the overall iron requirement during pregnancy is significantly higher than in non-pregnant women. The aim of the systematic review was to assess the effectiveness of dietary interventions in the prevention and treatment of iron-deficiency anemia in pregnant women based on randomized-controlled trials. The systematic review was based on the PRISMA guidelines and is registered in the PROSPERO database (CRD42021261235). The search was conducted within PubMed and Web of Science databases for the period until June 2021. The included randomized controlled trials presented effectiveness of dietary interventions in prevention and treatment of iron-deficiency anemia in pregnant women. From the total number of 7825 screened records, the final number of seven studies were included in the systematic review. The procedure of screening, inclusion, reporting, and assessment of the risk of bias while using the revised Cochrane risk of bias tool for randomized trials was conducted by two independent researchers. The studies included in the systematic review were conducted in populations of anemic pregnant women, or mixed populations of anemic and non-anemic pregnant women. The interventions described within the studies were associated with including fortified products, regular products, or dietary counselling. They were based on providing an increased amount of iron, providing an increased amount of multiple nutrients, or general counselling only, while effectiveness was compared with effectiveness of the placebo, supplementation, or control group. The study duration was diversified from a few weeks to half a year or longer. The major biochemical measure assessed within the included studies was hemoglobin. All applied dietary interventions, based on providing increased amount of iron, providing increased amount of multiple nutrients, or general counselling only, were effective. The majority of included studies were assessed as ones of a medium risk of bias. For some studies a high risk of bias was indicated, which resulted from a risk of bias arising from the randomization process, due to deviations from the intended interventions, and in selection of the reported result. Considering this fact, more randomized controlled trials should be planned and conducted in a rigorous manner to confirm the formulated observations of effectiveness of the studied interventions based on providing an increased amount of iron, providing an increased amount of multiple nutrients, or general counselling only.
Keywords: anemia; diet; iron; iron deficiency; iron intake; nutrition; pregnancy; pregnant; randomized controlled trials; vitamin C intake.