Abstract Background: Serum retinol binding protein (RBP4) is the binding protein for retinol, being delivered into the circulation through the carrier protein transthyretin (TTR) together with thyroxin (T4). RBP4 has also been recently indicated as a new adipokine implicated in insulin resistance and metabolism regulation. Objective: To investigate the role of RBP4 as early markers of fetal growth restriction (FGR) and preeclampsia (PE) in maternal serum during the first trimester of pregnancy. Materials and methods: Retrospective case control study in patients between the 12th and the 14th week of gestation. RBP4, TTR and T4 concentration was assessed in maternal serum of three groups of women: 15 and 14 patients later developing respectively FGR and PE were compared with 11 patients having a normal pregnancy. Results: All women were Caucasian and the mean maternal age was 33.62 years (±5.50). RBP4 resulted lower in the FGR than in the control group (11.00 versus 16.00 µg/ml, p < 0.05) and than in the PE group (15.00 µg/ml, p = 0.075), both in bivariate and multivariate analysis. No difference was observed in TTR and T4 concentration. Conclusions: RBP4 seems to play a role as early marker of FGR but not PE in first trimester maternal serum.