Additionally, factors such as religious beliefs, cultural practices, low education levels, and economic disparities contribute to higher rates of anemia during pregnancy.[12] Using the WHO diagnostic criteria for anemia during pregnancy (Hb < 110 g/L) in plateau areas may lead to overlooking pregnant women who do not appear anemic but may have developed ID, thus missing the opportunity to prevent IDA during pregnancy. This evidence concerns the gene GSTM1 and anemia (phenotype).