Challenges in determining body fat in pregnant women

Determining body composition in pregnant women is challenging as not all of the existing applicable methodologies can be used during pregnancy and not all of the methods have been properly standardized. The aim of this study was to compare the existing anthropometric methods for the evaluation of body composition, especially in pregnant women.

One hundred forty-seven pregnant volunteers aged [average (SD)] 31 years (± 4) in gestational week 32 (± 3) provided information on their age and prepregnancy body mass. Their height, current mass, skinfold thicknesses, and limb circumferences were measured. The body density and fat percentage were calculated according to 17 different anthropometric equations obtained from the literature. Data were analyzed with ANOVA.

For the same sample of pregnant women, the body fat percentages obtained using the existing anthropometric methods varied greatly (p < 0.0001) and ranged from 16% (± 5) to 38% (± 4); methods developed specifically for pregnant women yielded disturbingly large differences, with body fat values ranging from 16% (± 5) to 36% (± 6).

This study revealed large discrepancies among anthropometric methods for body composition assessment in pregnant women. As the results from the same sample obtained with different existing equations are wide ranging, the existing methodologies should be examined and improved before they can serve as sources of information regarding the health status of pregnant women.