Nutrition Support during Pregnancy

Nutrition support during pregnancy is complicated by the hypothalamic-pituitary-adrenal axis (HPA) changes of pregnancy [1] and the nutritional demands of the mother, placenta, and fetus. Women during the rst two trimesters of pregnancy are in an anabolic state, which results in lipogenesis [2], whereas, later in pregnancy, a catabolic state predominates and subsequent insulin resistance results in a rise in lipolysis and free fatty acids [3]. The rise of progesterone, cortisol, and insulin in the rst trimesters facilitates the anabolic systems [4]. In addition, the normal homeostatic mechanisms regulating appetite and food intake are modied to induce hyperphagia generated by a lack of hypothalamic response to leptin released from adipose tissue [5]. More specically, free fatty acids can be used for beta-oxidation for acetyl CoA and glycerol used for glucose synthesis [6]. The placenta plays a key role in the release of placental lactogen, which may mediate the lack of hormonal response to leptin and therefore immediate supply of transfer of nutrients to the fetus [7,8]. In fact, glucose and amino acids are the most important substrates crossing the

Introduction .................................................................................................................................... 331 Basis for Nutrient Recommendations for the Pregnant Mother ..................................................... 333 Recommended Dietary Intake ........................................................................................................ 333 Macronutrients ............................................................................................................................... 333

Calories/Protein ......................................................................................................................... 333 Lipids/Fatty Acids ..................................................................................................................... 334

Micronutrients ................................................................................................................................ 335 Folate and the B Vitamins ......................................................................................................... 335 Antioxidants: Vitamin C/E ........................................................................................................ 336 Vitamin A .................................................................................................................................. 336 Vitamin D .................................................................................................................................. 337 Calcium ..................................................................................................................................... 339 Iron and Zinc .............................................................................................................................340 Iodine......................................................................................................................................... 341

Maternal Conditions That Warrant Special Dietary Condition Considerations ............................. 342 Nutritional Enteral Supplements ............................................................................................... 342

Herbs .............................................................................................................................................. 342 Conclusion ..................................................................................................................................... 343 References ...................................................................................................................................... 343

fusion via glucose transporters (GLUTs) [10]. GLUT1 is the predominant rate-limiting transfer and is found in the microvillus and basal membrane of the syncytial barrier [10]. In a longitudinal examination of 6 women with normal glucose tolerance and 10 women with abnormal glucose tolerance, indirect calorimetry, endogenous glucose production examination (using [6-62H2]- labeled glucose), and insulin sensitivity (using a hyperinsulinemic/euglycemic clamp) were performed [11]. Increased fat mass was signicantly lower at 12-14 weeks of gestation in women with decreased pregravid insulin sensitivity (r = −0.52, p = 0.04). Diabetic pregnancies are associated with increased basal expression of GLUT1. Also positive expression is induced by ILGF1, placental GH, and hypoxia. Glucose and amino acid transfer adapts to maternal calorie intake, diet, and hormones [12]. Maternal plasma concentrations of amino acids fall during pregnancy, which is related to the metabolic ux via ketogenesis and gluconeogenesis in order to supply these critical nutrients to the fetus [13]. Maternal undernutrition however can impair this supply once the body stores are depleted resulting in not only intrauterine growth restriction of the fetus but also to adult risk of obesity, hypertension, and diabetes [7,14,15]. Conversely, maternal glucose intolerance results in fetal macrosomia and subsequent risks of delivery injuries and birth defects [16]. The complex nutritional process is summarized in the graphic demonstrated in Figure 19.1 and emphasizes the careful attention warranted in the dietary prescription in pregnancy. Energy expenditure and nitrogen assimilation is elevated for the growing fetal tissues; thus, macro and micronutrient needs are increased for the woman in pregnancy to meet the demands of the metabolic pathways involved.