Body Composition During Pregnancy: Longitudinal Changes and Method Comparisons

Abstract

The Pregnancy Obesity Nutrition and Child Health study is a longitudinal study of reproductive health. Here we analyzed body composition of normal-weight and obese Swedish women by three methods during each trimester of pregnancy. Cross-sectional and longitudinal fat mass estimates using quantitative magnetic resonance (QMR) and bioelectrical impedance analysis (BIA) (Tanita MC-180MA-III) were compared with fat mass determined by air displacement plethysmography (ADP) in pregnancy weeks 8-12, 24-26, and 35-37 in normal-weight women (n = 122, BMI = 22.1 ± 1.6 kg/m 2) and obese women (n = 29, BMI = 34.6 ± 3.6 kg/m 2). ADP results were calculated from pregnancy-adjusted fat-free mass densities. Mean fat mass by QMR and ADP were similar in obese women, although with wide limits of agreement. In normal-weight women, QMR overestimated mean fat mass in all trimesters, with systematic overestimation at low fat mass values in trimesters 1 and 3. In obese women, fat mass by BIA was grossly underestimated and imprecise in all trimesters, especially at higher values in trimester 2. In normalweight women, fat mass by BIA was moderately lower than by ADP in trimester 1, similar in trimester 2, and moderately higher in trimester 3. QMR and ADP assessed fat mass changes similarly in obese women, whereas BIA overestimated fat mass changes in normal-weight women. Mean fat mass and fat mass changes by QMR and pregnancy-adjusted ADP were similar in pregnant obese women. Mean fat mass by QMR and fat mass changes by BIA were higher than corresponding values determined by pregnancy-adjusted ADP in normal-weight women.

Physical activity during pregnancy and association with changes in fat mass and adipokines in women of normal-weight or with obesity

“…Body composition was measured by air-displacement plethysmography using the Bod Pod Gold Standard system (Bod Pod 2007 A, Life Measurement, Concord, CA, software versions 4.2.0 and 5.2.0.) using gestational-age specific equations according to our previously described protocol 29 . Leptin and adiponectin were analysed at the Clinical Chemistry Laboratory, Sahlgrenska University Hospital (accredited in accordance with the International Standard ISO 15189:2007).…”

Body composition helps: Differences in energy expenditure between pregnant and nonpregnant females

“…However, some limitations have been pointed out for the use of BIA in pregnant females. In a recent review, Bosaeus et al (2020) compared the performance of TANITA MC-180MA III, a BIA device, with other methods to estimate body composition in pregnant women concluding that TANITA MC-180MA III should not be used to estimate fat mass (FM) in pregnant women because it less accurate than other alternative methodologies like air displacement plethysmography. Moreover, it has been shown that BIA is less accurate than other methodologies, producing relatively large interindividual variations (Marshall et al, 2016).This method may underestimate total body water (TBW) in late pregnancy (Löf & Forsum, 2004a;Most, Marlatt, Altazan, & Redman, 2018) and the estimates of TBW can be influenced by the ratio of intracellular and extracellular water, commonly standardized in BIA devices (Shaikh et al, 2011;van Loan, Kopp, King, Wong, & Mayclin, 1995;Widen & Gallagher, 2014; but see Lukaski, Hall, & Siders, 2007).…”

“…However, some limitations have been pointed out for the use of BIA in pregnant females. In a recent review, Bosaeus et al (2020) compared the performance of TANITA MC—180MA III, a BIA device, with other methods to estimate body composition in pregnant women concluding that TANITA MC—180MA III should not be used to estimate fat mass (FM) in pregnant women because it less accurate than other alternative methodologies like air displacement plethysmography. Moreover, it has been shown that BIA is less accurate than other methodologies, producing relatively large interindividual variations (Marshall et al, 2016).…”

Adipose Tissue Development and Expansion from the Womb to Adolescence: An Overview

“…However, there is limited data on maternal body composition during gestation in adolescents or adults due to the changes in uterine contents and total body water that affect the technique’s underlying assumptions [ 90 ]. In adults, gains in whole-body FM occur throughout pregnancy, as assessed by four-compartment models [ 91 , 92 ], and ADP and quantitative magnetic resonance [ 93 ]. Furthermore, pregnant women experience marked increases in thigh and suprailiac skinfolds (which are surrogate measures of subcutaneous AT) during the first six months of gestation but mobilization of these adiposity depots in the last 10–12 weeks of pregnancy to enhance fetal growth [ 94 ].…”