Determinants of gestational weight gain in obese pregnant women

描述（由申请人提供）：在美国，肥胖妇女进入怀孕的数量在过去的30年里翻了一番多。然而，孕前肥胖并不是引起关注的唯一原因，因为三分之二的肥胖妇女的体重增加超过了2009年IOM的建议，并且迄今为止控制妊娠期体重增加的尝试都失败了。为了改善肥胖孕妇的体重管理，迫切需要提供关于能量摄入和能量消耗（身体活动）的具体循证建议；非怀孕个体体重增加的两个主要决定因素。作为LIFE-Moms（孕妇生活方式干预研究）的一项辅助研究，我们将评估80名肥胖妇女在怀孕期间（13至37周）和产后12个月的能量摄入和能量消耗，这些妇女随机接受强化生活方式干预以控制妊娠期体重增加。我们将检验这样一个假设，即体重增加超过IOM指南（“高增重者”）的肥胖孕妇会增加能量摄入，但与体重适当增加的孕妇（“正常增重者”）相比，在调整体重后，没有证据表明能量消耗会发生变化。主要结局变量为：1)孕期和产后12个月的能量摄入，采用能量平衡法和母亲能量摄入的数学模型测量；2)孕期自由生活能量消耗和睡眠代谢率（绝对值，根据母亲身体成分和胎儿大小进行调整）。次要结果包括测量体力活动和底物氧化的变化，能量摄入的决定因素，包括空腹瘦素、总饥饿素、肽YY、胆囊收缩素的浓度，能量消耗的决定因素，包括尿肾上腺素和去甲肾上腺素，空腹T3、T4和TSH的浓度。

DESCRIPTION (provided by applicant): In the U.S. the number of obese women entering pregnancy has more than doubled in the past 30 years. Pregravid obesity alone however is not the only cause for concern since two-thirds of obese women gain weight in excess of the 2009 IOM recommendations and attempts to manage gestational weight gain to date have failed. To improve weight management of obese pregnant women, there is a critical need to deliver specific evidence-based recommendations on energy intake and energy expenditure (physical activity); the two primary determinants of weight gain in non-pregnant individuals. As an ancillary study to LIFE-Moms (Lifestyle Interventions in Expectant Moms Study) we will evaluate energy intake and energy expenditure during pregnancy (13 to 37 weeks) and 12 months postpartum in 80 obese women randomized to receive an intensive lifestyle intervention to manage gestational weight gain. We will test the hypothesis that obese pregnant women with weight gain above the IOM guidelines, 'High Gainers', will have increased energy intake but no evidence for changes in energy expenditure after adjustment for the weight gained when compared to women with appropriate gestational weight gain, 'Normal Gainers'. The primary outcome variables are 1) energy intake during pregnancy and 12 months postpartum measured with the energy balance method and with a mathematical model of maternal energy intake 2) the free-living energy expenditure and sleeping metabolic rate (absolute and adjusted for maternal body composition and fetal size) during pregnancy. Secondary outcomes include measurement of changes in physical activity and substrate oxidation, determinants of energy intake including fasting concentrations of leptin, total ghrelin, peptide YY, cholecystokinin and determinants of energy expenditure including urinary epinephrine and norepinephrine, fasting concentrations of T3, T4 and TSH.