Purpose: To analyze how maternal body figures affect estimated fetal weights (EFW). Subjects and methods: Cases delivered between 28 and 41 weeks of gestation from 2005 to 2010 in our university hospital were enrolled. Retrospective analysis based on medical records was performed to evaluate the association between EFW at just before delivery and maternal body figure. Variables that affect EFW were analyzed by multivariate regression analysis. Results and Discussion: Analysis of 3,417 cases showed that gestational days, fetal gender, maternal weight, and maternal height were associated with EFW. Based on the results of the multivariate regression analysis, EFW was expressed as the following model: EFW=-4,825+4.7×maternal height+5.7×pre-pregnancy weight+24.2×gestational days+62.5×fetal gender (male=1, female=0). Conclusion: Distribution of EFWs tends to be smaller in the case of smaller maternal body figures, including maternal weights and heights. This formula based on the present results may be useful for fetal growth assessment in small pregnant women.