Given that 21 of the included studies did not report data by trimester, studies were also grouped according to maternal factors studied in association with fetal/neonatal and infant outcomes as (1) maternal diet (n = 3 reviews), (2) maternal anthropometry (n = 8 reviews), (3) maternal hemoglobin (Hb)/anemia (n = 5 reviews), (4) maternal micronutrient status (n = 6 reviews), (5) maternal supplementation with individual or combined macro/micronutrients (n = 28 reviews), detailed in Supplementary Files Table S3. This evidence concerns the gene GSTM1 and anemia.