Objective: To compare maternal ferritin levels across pregnancies with fetal growth restriction including SGA and IUGR compared to appropriate for gestational age (AGA). Methods: Three groups were enrolled: AGA, SGA (birth weight below 10th percentile for gestational age with no placental insufficiency findings), and IUGR (birth weight below 5th percentile for gestational age accompanied by abnormal umbilical artery Doppler waveforms and/or oligohydramnios). Maternal serum ferritin samples were obtained at gestational weeks 34 through 36, and delivery occurred at or beyond 36 weeks. Results: A total of 126 pregnancies with AGA (36%), SGA (40%), and IUGR (24%) were enrolled. The mean maternal serum ferritin level was higher in the IUGR group than in the AGA group (59 mu g/l versus 32.5 mu g/l, p < 0.001). A maternal serum ferritin cutoff of 48 mu g/l was found to be optimal for distinguishing between IUGR and AGA with a sensitivity of 67.7%, specificity of 92%, PPV of 84%, NPV of 82%, diagnostic accuracy of 82.7%, LR + of 8 and LR-of 0.3, respectively. Conclusion: Maternal serum ferritin levels differ in pregnancies with IUGR. The role of maternal serum ferritin measurements as a clinical tool for distinguishing different forms of fetal growth restriction warrants further investigation.