To evaluate impact of vitamin D supplemental therapy (VD-ST) and iron ST (IST) on hemoglobin concentration (HC) in pregnant women. Patients & Methods: 187 women pregnant were clinically evaluated and gave blood samples at 1st trimester for estimation of HC and serum 25OH-VD, ferritin concentration (FC), hepcidin (HPC) and interleukin- 6 (IL-6). Women were categorized according to the levels of estimated parameters into control and study groups A-D. Women of groups A and C received VD-ST alone, group B received IST alone and group D received both ST. At delivery, HC, extent of change and frequency of pregnancy- associated anemia (PAA) were determined. Results: At 1st trimester, 71.7% women were anemic and 38.5% had hypoferremia, 77% had VD deficiency (VDD) and 59.4% had both VDD and PAA. Serum HPC and IL-6 levels in anemic women especially those had VDD were significantly higher than control women. At delivery, 35% of control women developed PAA and mean HC was significantly lower than 1st trimester HC with a median deficit of 4.72 gm/dl (IQR: 2.8-6.4) among studied population. Frequency of anemic women in groups B-D was decreased at delivery by 21.7%, 30.8% and 30.6%, respectively. Statistical analyses defined high serum HPC and IL-6 levels at 1st trimester as specific early predictors for PAA development, but early institution of ST especially VD-ST is one of the best significant predictors for improved HC at time of delivery. Conclusion: VDD, hypoferremia, higher HPC and IL-6 levels constitute a vicious circle entrapping pregnant women and inducing iron deficiency anemia at delivery. Early institution of VD-ST and IST can burst this circle and induce improvement of HC up to normal range in about 30% of women presented by PAA. Thus, early estimation of HC and serum VD can be used as a guide for early institution of ST.