King Janet C
Children's Hospital Oakland Research Institute, the University of California at Berkeley, and the University of California at Davis, Oakland, California 94609, USA.
Annu Rev Nutr. 2006;26:271-91. doi: 10.1146/annurev.nutr.24.012003.132249.
About one third of all pregnant women in the United States are obese. Maternal obesity at conception alters gestational metabolic adjustments and affects placental, embryonic, and fetal growth and development. Neural tube defects and other developmental anomalies are more common in infants born to obese women; these defects have been linked to poor glycemic control. Preeclampsia, a gestational disorder occurring more frequently in obese women, appears to be due to a subclinical inflammatory state that impairs early placentation and development of its blood supply. Fetal growth and development during the last half of pregnancy depends on maternal metabolic adjustments dictated by placental hormones and the subsequent oxygen and nutrient supply. Maternal obesity affects these metabolic adjustments as well. Basal metabolic rates are significantly higher in obese women, and maternal fat gain is lower, possibly in response to altered leptin function. The usual increase in insulin resistance seen in late pregnancy is enhanced in obese mothers, causing marked postprandial increases in glucose, lipids, and amino acids and excessive fetal exposure to fuel sources, which in turn increases fetal size, fat stores, and risk for disease postnatally. Impaired glucose tolerance, gestational diabetes, and hyperlipidemia are more common among obese mothers. To date, little attention has been given to the role of diet among obese women in preventing these problems. However, studies of women with impaired glucose tolerance show that replacing refined carbohydrates and saturated fat with complex, low-glycemic carbohydrates and polyunsaturated fatty acids improves metabolic homeostasis and pregnancy outcomes. Thus, current dietary guidelines regarding the amount and type of carbohydrates and fat for nonpregnant women seem appropriate for pregnant women as well.
在美国，约三分之一的孕妇肥胖。怀孕时的母体肥胖会改变孕期代谢调节，并影响胎盘、胚胎及胎儿的生长发育。神经管缺陷和其他发育异常在肥胖女性所生婴儿中更为常见；这些缺陷与血糖控制不佳有关。先兆子痫是一种在肥胖女性中更频繁出现的孕期疾病，似乎是由于一种亚临床炎症状态，这种状态会损害早期胎盘形成及其血液供应的发育。妊娠后半期胎儿的生长发育取决于由胎盘激素决定的母体代谢调节以及随后的氧气和营养供应。母体肥胖也会影响这些代谢调节。肥胖女性的基础代谢率显著更高，且母体脂肪增加较少，这可能是对瘦素功能改变的一种反应。肥胖母亲在妊娠晚期常见的胰岛素抵抗增加更为明显，导致餐后血糖、脂质和氨基酸显著升高，以及胎儿过多暴露于营养物质中，这反过来又会增加胎儿大小、脂肪储备以及出生后患病风险。葡萄糖耐量受损、妊娠期糖尿病和高脂血症在肥胖母亲中更为常见。迄今为止，肥胖女性的饮食在预防这些问题中的作用很少受到关注。然而，对葡萄糖耐量受损女性的研究表明，用复合、低血糖碳水化合物和多不饱和脂肪酸替代精制碳水化合物和饱和脂肪可改善代谢稳态和妊娠结局。因此，目前针对非孕妇碳水化合物和脂肪的量及类型的饮食指南似乎也适用于孕妇。
