The goal of this study was to analyze the relationship between maternal serum levels of transthyretin (TTR), retinol-binding protein 4 (RBP4), and the birth weight in fetal growth restriction (FGR). Materials and Methods: Retrospective case control study including 30 FGR patients and 30 normal healthy pregnancies with the same week of gestation. Serum concentrations of TTR and BRP4 were assessed by ELISA; placenta concentration of TTR and RBP4 by Immunohistochemical method. Results: FGR patients were characterized by reduced TTR compared to controls. The concentration of TTR in FGR was 4.05 ± 0.32 ng/ml and control was 5.20 ± 0.27 ng/ml (p < 0.05); however, RBP4 remained unchanged in two groups (FGR vs. controls RBP4 35.36 ± 2.15 ng/ml vs. 35.09 ± 1.58 ng/ml, p > 0.05). The expression of TTR had a positive correlation with the birth weight in FGR (r = 0.620, p < 0.05). Placenta of FGR showed a strong staining for TTR, while control was only weak by using immunohistochemistry. The expression of RBP4 was poor in FGR and control. Conclusions: The higher the maternal plasma in TTR, the better the fetal development. TTR may be the marker to diagnose FGR and forecast the sequelae of the fetus.