Pregnant women are a special population where notable anthropometric changes occur between the periods of gestation and delivery. Measurements of the body, specifically, in the lower torso region change significantly, and these changes need to be considered while designing a user-centric product, especially maternity wear. The sizing chart and the grading rules followed for pregnant women are not reflecting the anthropometric changes of the pregnant women to a desired level of accuracy. One of the primary reasons for this deficit in the sizing chart is the lack of data on pregnant women anthropometry. Thus, the purpose of this study is (1) to document the anthropometrical changes in a sample population of pregnant women, starting from gestation to delivery and (2) to develop a statistical predictive model estimating the measurement changes that can be applied for product development. Body measurement data from the 3D body scans of 12 subjects scanned at five different times throughout their gestation period were used in this study for statistical model development. Based on the developed model, the body measurement changes of pregnant women can be estimated with higher level of accuracy and minimum variance. Sizing chart and grading rules can be easily created using the estimated measurements. Additionally, the cross-sections extracted from the 3D scans can provide information related to orientation of shape changes, which could further support optimal product design.