Background: The aim is to assess the levels of fatty acids (FAs) in pregnancies with small for gestational age (SGA) and adequate for gestational age (AGA) fetuses, constituting an association between FAs and fetal growth; according to the role of FA, lower levels were expected in SGA.Materials and Methods: This was an analytical cross-sectional study including pregnant women with gestational ages of 26–36 weeks with AGA and constitutionally SGA fetuses diagnosed by ultrasonography. The levels of saturated, trans, monounsaturated, and polyunsaturated fatty acids were measured using centrifugation and liquid chromatography. Student’s t test and general linear model using gestational age as covariant were used to compare the levels of FAs and the groups (AGA and SGA). Chi-square was used to evaluate the association between groups and studied variables. Pearson correlation coefficient and linear regression were used to evaluate the correlation between the levels of FAs and gestational age.Results: Peripheral blood was collected from 67 pregnant women, 3 of whom were excluded from the study. No significant statistical differences were observed between SGA (n = 40) and AGA (n = 24) in relation to saturated, trans, monounsaturated, and polyunsaturated fatty acids (p > 0.05). There was not significant correlation between saturated, trans, monounsaturated, and polyunsaturated FAs and gestational age (p > 0.05).Conclusion: The levels of saturated, trans, monounsaturated, and polyunsaturated FAs were similar in constitutionally SGA and AGA fetuses.