Fe-deficiency anaemia is common during pregnancy and can lead to serious health consequences for mothers and babies. Antenatal Fe supplementation is associated with lower anaemia prevalence and improved pregnancy outcomes, and the WHO recommends daily oral Fe (30–60 mg) with folic acid (0·4 mg) during pregnancy. However, data on uptake and adherence in many low- and middle-income countries remain fragmented and outdated. We conducted a secondary analysis of Demographic and Health Surveys from sixty-nine low- and middle-income countries to assess uptake and adherence to Fe-containing supplements and explore associations with socio-demographic characteristics and antenatal care (ANC). Overall, 86 % of respondents reported receiving Fe supplements during pregnancy. Among these women, 46·1 % consumed ninety or more supplements, 23·3 % consumed 120 or more, and only 7·1 % consumed 180 or more. Higher education, wealth, and media access were strongly associated with increased odds of initiating supplementation (OR: 1·32; 95 % CI: 1·25, 1·38; OR: 1·29; 95 % CI: 1·20, 1·38; OR: 1·15; 95 % CI: 1·05, 1·26, respectively) and adhering to the regimen (OR: 1·16; 95 % CI: 1·12, 1·21; OR: 1·21; 95 % CI: 1·13, 1·30; OR: 1·14; 95 % CI: 1·08, 1·20, respectively). Early ANC attendance was also associated with higher supplement consumption. Country-specific ANC guidelines are needed to provide clear guidance on the timing and frequency of ANC attendance and supplementation.

The object of the present study was to investigate the levels of serum transferrin receptor (sTfR) and its response to Fe supplementation in Fe-deficient children and the role of sTfR in detecting Fe deficiency and assessing the efficacy of Fe supplementation. According to the diagnostic standard, 1006 children, aged 6–14 years in Fangshan district, Beijing, Peoples Republic of China, were divided into four groups: normal; Fe store depletion (IDs); Fe deficiency erythropoiesis (IDE); Fe deficiency anaemia (IDA). sTfR was determined and transferrin receptor-ferritin (TfR-F) index was calculated in 238 children, sixty-four normal and 174 Fe deficient. Children were administered a NaFeEDTA capsule containing 60 mg Fe once per week for the IDs and IDE groups and three times per week for the IDA group for nine consecutive weeks. The parameters reflecting Fe status and sTfR were determined before and after Fe supplementation. The levels of sTfR and TfR-F index in Fe-deficient children were significantly higher than those in the normal group. The receiver operating characteristic curve showed that sTfR has proper diagnostic efficacy for functional Fe deficiency. After Fe supplementation, the level of sTfR was significantly decreased in children with IDs, but not in children with IDE and IDA, while TfR-F index was significantly decreased in Fe-deficient children. sTfR is a reliable indicator for detecting functional Fe deficiency, and TfR-F index is a sensitive parameter for assessing the efficacy of Fe supplementation.