. Author manuscript; available in PMC: 2015 Jun 1.

Published in final edited form as: Eur J Clin Nutr. 2014 Mar 26;68(6):643–652. doi: 10.1038/ejcn.2014.40

Table 2.

Equations for estimating body fat in pregnancy

Anthropometric equations	Population
Paxton (1) fat change from 14 to 37 weeks:	White, black and Hispanic women in New York City, NY, USA
Fat change, kg = 0.77 (weight change, kg) +0.07 (change in thigh skinfold thickness, mm) - 6.13.	White, black and Hispanic women in New York City, NY, USA
Paxton (1) body fat mass at term (37 weeks):
Fat mass, kg = 0.40 (weight at week 37, kg) + 0.16 (biceps skinfold thickness at 37 wk, mm)− 0.15 (thigh skinfold thickness at 37 weeks, mm)- 0.09 (wrist circumference at 37 weeks, mm)+0.10 (prepregnancy weight, kg) −6.56 (2).
Huston Presley (2) body fat mass at 30 weeks:	Predominantly white women in Cleveland, OH, USA
Fat mass, kg = 0.33529 (weight, kg) +0.65664 (triceps skinfold thickness, mm)‒0.4373 (subscapular skinfold thickness, mm)+0.43461 (suprailliac skinfold thickness, mm)‒13.0538.	Predominantly white women in Cleveland, OH, USA
Equations for deriving arm fat area (AFA) and arm muscle area (AMA) (3)
AMA (cm²) = [mid-upper arm circumference-(triceps skinfold×π)]²/4π
AFA (cm²)=(mid-upper-arm circumference²/4π -arm muscle area) (3)
Equation for body composition from body density, total body water and body weight
Siri (4, 5) equation for body composition:
Fat mass, kg = [2.118 × (BV/body weight)] − (0.78 × TBW/body weight) − 1.354] × 100

Abbreviations: BV, body volume (l); TBW, total body water (kg).