Determination of Maternal Body Composition in Pregnancy and Its Relevance to Perinatal Outcomes

Abstract

Three models and 10 specific methods for determining maternal body composition are discussed and their perinatal relevance reviewed. English language publications (1950 to January 2004) were searched electronically and by hand. Search terms included "body composition," "human," " pregnancy," "obesity," "adiposity," "regional," "2-, 3-, 4-component," "truncal," "peripheral," "central," "visceral" along with specific techniques and outcomes listed subsequently. Three models of body composition are described: 2-component being fat and fat-free mass; 3-component being fat, water, and protein; and 4-component being fat, water, protein, and osseous mineral. Ten techniques of body composition assessment are described: 1) anthropometric techniques including skinfold thicknesses and waist-hip ratio; 2) total body water (isotopically labeled); 3) hydrodensitometry (underwater weighing); 4) air-displacement plethysmography; 5) bio-impedance analysis (BIA); 6) total body potassium (TBK); 7) dual-energy x-ray absorptiometry (DEXA); 8) computed tomography (CT); 9) magnetic resonance imaging (MRI); and 10) ultrasound (USS). Most methods estimate total adiposity. Regional fat distribution-central (truncal) compared with peripheral (limb) or visceral compared with subcutaneous-is important because of regional variation in adipocyte metabolism. Skinfolds, DEXA, CT, MRI, or USS can distinguish central from peripheral fat. CT, MRI, or USS can further subdivide central fat into visceral and subcutaneous. Perinatal outcomes examined in relation to body composition include pregnancy duration, birth weight, congenital anomalies, gestational diabetes, gestational hypertension, and the fetal origins of adult disease. A few studies suggest that central compared with peripheral fat correlates better with birth weight, gestational carbohydrate intolerance, and hypertension. Means of accurately assessing maternal body composition remain cumbersome and impractical, but may more accurately predict perinatal outcomes than traditional assessments such as maternal weight.

Retinol-binding protein-4 is not strongly associated with insulin sensitivity in normal pregnancies.

“…Most measurements of fat mass are based on a constant and known composition of hydrated and dry tissue. However, in pregnancy, a relative excess of body water can be observed and consequently the usual assumptions made for the fat-free mass do not hold (23). Importantly, with regard to insulin resistance, central visceral fat, in particular, is strongly associated with insulin resistance and type 2 diabetes.…”

Body composition in pregnancies of adolescents and mature women and the relationship to birth anthropometry

“…Anthropometric methods for estimating body fat have not been shown to be less accurate than those using more sophisticated methods like hydrodensitometry (Presley et al, 2000), dual-energy X ray absorptiometry scan and bioelectrical impedence analysis (McCarthy et al, 2004), and anthropometric measurements are convenient, inexpensive, easy and safe. The formula that has been used was developed on non-pregnant women, as there has been limited epidemiological research in the area of body composition in pregnancy.…”

Follistatin-Like 3 Across Gestation in Preeclampsia and Uncomplicated Pregnancies Among Lean and Obese Women

“…Waist to hip ratio (WHR) was calculated using measurements conducted at study enrollment in the first trimester before the gravid uterus had begun to change the contour of the participant's mid-abdomen. 28 The body adiposity index was calculated using the formula from Bergman et al 29 (hip circumference)/(height) 1.5 À 18.…”