临床实践指南：加拿大女性营养共识（六）

前情提要

• 临床实践指南：加拿大女性营养共识（一）

• 临床实践指南：加拿大女性营养共识（二）

• 临床实践指南：加拿大女性营养共识（三）

• 临床实践指南：加拿大女性营养共识（四）

• 临床实践指南：加拿大女性营养共识（五）

第五章　妊娠期营养

概述

1. 高质量的饮食摄入和适当的食物选择对所有孕妇都重要，可通过遵循适用于妊娠期的加拿大饮食指南来实现。食物选择应强调从4类食物中选择多种营养丰富的食物，而不是高能量、低营养食物。营养丰富、能量适当的饮食将有助于确保女性自己的营养需求得到满足，并促进胎儿在整个妊娠期的健康发育。（III）

2. 支持怀孕所需的能量（对于孕前体重指数18.5～25的女性）适中，孕前期不建议增加能量摄入，孕中期和孕后期建议分别增加340和450kcal/d。这一般相当于在孕中期和孕后期每天只额外增加2～3份加拿大饮食指南里4类食物中任何食物。（III）孕前体重指数超过25kg/m2的女性能量需求尚不确定。

推荐意见

1. 所有女性怀孕后尽早并定期测量和讨论妊娠期体重增长是可行的。对怀孕相关体重增长范围的建议应该基于该女性孕前体重指数（见表6）。体重增长在推荐范围内将有助于优化孕产妇、婴儿和儿童的健康结局。（III-A）

2. 没有达到特定孕龄推荐的体重增长低限或超过了高限的女性需要额外的随访和评估。应鼓励她们加快或减缓体重增长速度，使其每周体重增长速度在推荐范围内，直至生产。（III-A）

3. 支持女性了解妊娠期关注的特定营养素如何达到推荐量，包括叶酸、铁、胆碱、ω-3脂肪酸和碘。（III-A）

4. 遵循2015年加拿大妇产科医师学会指南，孕妇要补充叶酸。所怀后代有神经管畸形中到高风险的孕妇应每天从复合维生素中分别补充1mg和4mg的叶酸，如果所怀后代患神经管畸形风险高，她们应在怀孕前12周开始每天补充4mg叶酸，怀孕后每天补充0.4～1mg直至断奶。（II-3A）提醒女性每日复合维生素摄入不要超过一天的剂量。（III-B）

5. 向身体健康的孕妇推荐含有铁元素16～20mg的补充剂。有铁缺乏生化指标证据的女性可能需要治疗剂量的铁（如妊娠期任何时间点血红蛋白水平低下和血清铁蛋白＜30μg/L）。（I-A）

6. 有新的证据表明胆碱（II-2B）、ω-3脂肪酸（I-A）和碘（I-B）是重要的营养素，可能在孕妇摄入的饮食中有限。随着妊娠的进展，和孕妇探讨富含这些营养素的食物（如鸡蛋富含胆碱、脂肪多的鱼和坚果/种子富含ω-3脂肪酸、海水鱼甲基汞含量低及碘盐）。

7. 强调妊娠期限制或避免吃某些食物的重要性（如避免潜在细菌污染的食物和甲基汞含量高的鱼）。许多草药在妊娠期应被限制或避免使用（见附录B）。（III-A）

8. 遵循2010年加拿大妇产科医师学会指南对于妊娠期饮酒的建议。有证据表明，妊娠期饮酒会对胎儿带来危害。（II-2）孕期少量饮酒对胎儿安全或危害的证据不足。（III）

Chapter 5: Nutrition in Pregnancy

Summary Statements

1. High-quality dietary intake and appropriate food selections are important for all pregnant women, and can be achieved by following Canada's Food Guide as applied to pregnancy. Food selections should emphasize choosing a variety of nutrient-dense foods from all 4 food groups, as opposed to energy-dense, nutrient-poor foods. A nutrient-rich, energy-appropriate diet will help to ensure a woman's own nutritional requirements are met and facilitate healthy development of her fetus throughout the pregnancy. (III)

2. The amount of energy required to support pregnancy (for women with a pre-pregnancy body mass index of 18.5 to 25) is modest, with no recommended increase in calorie intake during the first trimester and an increase of only 340 and 450 kcal/day in the second and third trimesters, respectively. This generally equates to only 2 to 3 additional Canada's Food Guide servings per day from any of the 4 food groups in the second and third trimesters. (III) Energy requirements for women with a pre-pregnancy body mass index above 25 kg/m² are not well established.

Recommendations

1. Measure and discuss weight gain for pregnancy with all women as early in pregnancy and as regularly as is feasible. Recommendations for the range of pregnancy-related weight gain should be based on the woman's pre-pregnancy body mass index (Table 6). Gaining weight within recommended ranges will help to optimize maternal, infant, and child health outcomes. (III-A)

2. Women who have not met the minimum or have exceeded the maximum amount of weight gain recommended for a specific gestational age require additional follow-up and assessment. They should be encouraged to increase or slow their rate of weight gain to fall within the recommended ranges of weekly rate of gain until delivery. (III-A)

3. Support women in understanding how to meet recommendations for specific nutrients of concern during pregnancy, which include folate, iron, choline, omega-3 fatty acids, and iodine. (III-A)

4. Follow the 2015 Society of Obstetricians and Gynaecologists of Canada guideline for the supplementary use of folic acid by pregnant women. Pregnant women at low or moderate risk for bearing an offspring with a neural tube defect should consume 0.4 and 1 mg folic acid, respectively, in a daily multivitamin or if they are at high risk for bearing offspring with neural tube defects, a 4.0 mg folic acid supplement 12 weeks prior to and after conception followed by 0.4 to 1 mg until weaning. (II-2A) Caution women not to take more than 1 daily dose of their multivitamin. (III-B)

5. Recommend a supplement containing 16 to 20 mg of elemental iron to pregnant women who are in good health. Therapeutic doses of iron may be required for women demonstrating biochemical evidence of iron deficiency. (e.g., a low hemoglobin and a serum ferritin <30 ug/L at any point during pregnancy). (I-A)

6. Emerging evidence suggests that choline (II-2B), omega-3 fatty acids (I-A), and iodine (I-B) are important nutrients that may be limited in the diets that pregnant women consume. Discuss foods rich in these nutrients (e.g., eggs for choline; fatty fish and nuts/seeds for omega-3 fatty acids; saltwater fish low in methylmercury; and iodized salt) with women as the pregnancy progresses.

7. Emphasize the importance of limiting or avoiding certain foods during pregnancy (e.g., avoid foods potentially contaminated with bacteria and fish with high levels of methylmercury). Many herbs should be limited or avoided during pregnancy (Appendix B). (III-A)

8. Follow the 2010 Society of Obstetricians and Gynaecologists of Canada guideline for alcohol use during pregnancy. There is evidence that alcohol consumption in pregnancy can cause fetal harm. (II-2) There is insufficient evidence regarding fetal safety or harm at low levels of alcohol consumption in pregnancy. (III)

翻译：肖慧娟（天津市第三中心医院营养科）