Reduction of subcutaneous mass, but not lean mass, in normal fetuses in Denver, Colorado

• Published in: American journal of obstetrics and gynecology 2001-10, Vol.185 (4), p.839-844
• Main Authors: Galan, Henry L., Rigano, Serena, Radaelli, Tatjana, Cetin, Irene, Bozzo, Maddalena, Chyu, Jacquelyn, Hobbins, John C., Ferrazzi, Enrico
• Format: Article
• Language: English
• Subjects: Adipose Tissue - diagnostic imaging; Adult; Altitude; Biological and medical sciences; Body Composition - physiology; Body Mass Index; Colorado; Diseases of mother, fetus and pregnancy; fat; Female; Fetal Growth Retardation - diagnostic imaging; Fetus; Gynecology. Andrology. Obstetrics; Humans; intrauterine growth restriction; Italy; Medical sciences; Muscle, Skeletal - diagnostic imaging; Pregnancy; Pregnancy. Fetus. Placenta; Probability; Reference Values; Sensitivity and Specificity; subcutaneous tissue; Ultrasonography, Prenatal - methods
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1067/mob.[phone]

Objective: To test the hypothesis that reduced birth weight in normal fetuses born at moderately high altitude (Denver), compared with the birth weight in normal fetuses born at sea level (Milan), is caused by a reduction in both lean mass and subcutaneous fat mass. Study Design: Ninety-four normal singleton pregnancies (46 in Denver, 48 in Milan) had serial ultrasonographic axial images obtained to assess subcutaneous tissues of fetuses as a measure of body fat. The abdominal wall thickness and mid upper arm and mid thigh were examined. The equation was: Subcutaneous tissue equals total cross-sectional area minus bone and muscle area. Lean mass included the area of muscle and bone, head circumference, and femur length. Results: Gestational age at delivery was similar between groups. Birth weight was less at Denver's altitude (2991 ± 79 g versus 3247 ± 96 g; P =.04). Abdominal wall thickness, mid upper arm, and mid thigh subcutaneous tissues measurements were significantly reduced at Denver's altitude and increased further in significance with advancing gestational age. Lean mass measurements were similar between groups. Conclusions: The reduced birth weight of the newborns in Denver was the result of a reduction in fetal subcutaneous fat tissue and not lean mass. Ultrasonography can be used to follow subcutaneous measurements longitudinally and to detect differences, and potentially disease processes, in study populations. (Am J Obstet Gynecol 2001;185:839-44.)