Pilot Study Examining Pregnancy-specific Equations to Estimate Percent Body Fat in an Overweight/obese Pregnant Hispanic Population

Background and Purpose: Over half of women entering pregnancy are overweight or obese, increasing metabolic risk. This pilot study investigated whether established equations for estimating maternal percent body fat using anthropometry are accurate for Hispanic, overweight or obese pregnant women. Methods: The Siri technique of calculating percent body fat from direct measurements of body density and total body water was the gold-standard. Other pregnancy-specific equations were also examined. The study population included 15 normoglycemic, pregnant Hispanic women in their third trimester (33.2±1.9 gestational week) with a pre-pregnancy body mass index ≥25 to <40kg/m2 , and with no history of chronic disease, or illicit drug, cigarette or alcohol use. Five skinfold sites, pre-pregnancy weight, current weight, and wrist circumference were measured. Body density was measured using air displacement plethysmography. Total body water was measured using 2H2O. Results: Paired t-tests showed that the Paxton equation (intended for use at gestational week 37) overestimated percent body fat compared to the Siri method, p<0.001, whereas the Presley equation (intended for use at gestational week 30) produced statistically similar results to the gold-standard, p=0.842. Discussion: Using skinfold thickness measurements and the Presley equation to assess percent body fat may be useful and accessible for this population