Background: The purpose of this study was to construct a nomogram of the preload index (PLI) value obtained from the fetal inferior vena cava, and to establish the changes in PLI corresponding to gestational age in human Japanese fetuses. Materials and Methods: We performed a retrospective, cross-sectional study on 469 normal fetuses between 15 and 40 weeks of gestation. Using pulsed Doppler ultrasonography, the PLI in the fetal inferior vena cava was measured, and a nomogram was constructed using regression analysis to generate curves for the 5th, 10th, 50th and 95th percentiles. Results: The PLI decreased gradually with advancing gestational age. Conclusions: We generated a PLI nomogram from data obtained from inferior vena cava PLI measurements in human Japanese fetuses. These data can be utilized for evaluating the preload condition in compromised fetuses, especially those with hydrops fetalis.