Total body fat, assessed using a three-component model (y) versus total body fat, assessed using a two-component model (x) in 17 healthy women [12] plotted around the line of identity. The fat-free mass density used in the two-component model is also given. (A) Before pregnancy, FFM density = 1.1 g/mL [6,13]; (B) Gestational week 14, FFM density = 1.099 g/mL [2]; (C) Gestational week 32, FFM density = 1.092 g/mL [2]; (D) 2 weeks postpartum, FFM density = 1.094 g/mL [5]. FFM, fat-free mass; TBF3CM, total body fat assessed using a three-component model; TBF2CM, total body fat, assessed using a two-component model.