I. Importance of nutrition for women of childbearing age After pubertal sexual development, women enter the stage of sexual maturity and have the ability to bear children. Women who have the ability to bear children are also known as women of childbearing age, which generally starts at the age of 18 and lasts for about 30 years. Women of childbearing age have strong sexual functions, mature ovaries that secrete sex hormones, regular ovulation cycles, physiological adjustments and adaptations, and appropriate nutritional reserves, so that they can successfully carry out pregnancy and breastfeeding and reproduce the next generation. In the modern society where human beings pay attention to the quality of reproduction and the health of both mother and child, nutrition of women of childbearing age has been receiving more and more special attention. Good nutrition for young women of childbearing age is of paramount importance as it is not only about them but also closely related to the health of their offspring. Nutrition is a continuous life process, and a growing body of research has found a link between nutrition in women of childbearing age and the health of their offspring. A variety of maternal nutrients during childbearing age and pregnancy have a significant impact on the growth and development of the fetus, and both deficiencies and excesses can result in poor pregnancy outcomes. Nutritional problems and causes in women of childbearing age Generally speaking, with sufficient nutritional reserves, coupled with an abundance of food and improved health care, women’s nutritional and health conditions will improve markedly, but in reality young women of childbearing age are faced with a number of nutritional problems, as indicated by a survey of China’s nutritional and health status in 2002, which showed that low body weight or malnutrition accounted for 7.7 per cent of the total (about 28 million), and that the prevalence of anaemia among women of childbearing age was about 20 per cent. The prevalence of anemia among women of childbearing age is about 20% (72 million). On the other hand, the number of overweight and obese people is about 72 million, 17 million people suffer from high blood pressure and 2.8 million people suffer from diabetes. Among the many factors affecting women’s nutrition and health (poor lifestyle, poor environmental factors, and poor medical conditions), poor lifestyle has the most significant impact on health, and the most prominent manifestation of poor lifestyle is irrational nutrition. The main reason why young women of childbearing age have many nutritional problems is the lack of nutritional knowledge, and there are still many misunderstandings about nutrition, and they do not fully realize the importance of reasonable nutrition to health. Young women’s nutritional problems are mainly manifested in the following aspects: 1, blind dieting to lose weight, insufficient intake of staple foods 2, irrational eating habits, too few breakfasts 3, irrational dietary structure 4, too much reliance on health food or functional food 3, the importance of dietary nutrition for pregnant women pregnancy is a complex physiological process, in order to achieve a successful pregnancy, the physiological state of the pregnant woman and the metabolism of the larger adaptive changes to meet the maternal reproductive health of the mother during pregnancy. In order to have a successful pregnancy, the physiological state and metabolism of pregnant women undergo greater adaptive changes to meet the growth and development of the reproductive organs of the mother and the fetus during pregnancy, as well as to provide nutritional reserves for postpartum lactation. Nutritional status during pregnancy has a critical impact on the growth and development of the fetus and on its health in adulthood. Compared with non-pregnant women, pregnant women have increased requirements for energy and various nutrients, especially energy, protein, essential fatty acids, calcium, iron, folic acid, vitamin A and other micronutrients. In order to meet the increased need for various nutrients during pregnancy, food intake during pregnancy also increases accordingly, but the composition of the diet should still consist of a balanced diet composed of a wide variety of foods, which should be rich in variety and nutrients, and need not be avoided. If the diet cannot meet the nutritional needs for various reasons, vitamin and mineral supplements can be used reasonably under the guidance of a doctor. Different periods of pregnancy, the embryo’s development speed is different, pregnant women’s physiological state, the body’s metabolic changes and the demand for nutrients are also different. Fourth, the nutritional needs of early pregnancy Early pregnancy fetal growth and development is relatively slow, this time the nutritional requirements and pre-pregnancy there is no big difference. It is worth noting that most of the pregnant women in this period will appear nausea, vomiting, decreased appetite and other pregnancy reactions, these reactions often change the eating habits of pregnant women, and therefore lead to eat less food, may cause folic acid, zinc, iodine and other micronutrient deficiencies, which increases the risk of fetal malformations, and severe pregnancy reactions will also affect the development of the fetus. Early pregnancy should pay attention to the following points: (a) choose easy-to-digest, appetite-boosting food Early pregnancy by the increased secretion of progesterone affected by a series of changes in the function of the digestive system, pregnant women are prone to satiety and bloating, constipation, indigestion and regurgitation and other symptoms, the majority of early pregnancy women’s appetites will be reduced or change in taste. Therefore, during this period of time, light, palatable meals can enhance appetite, easy to digest, and is conducive to reducing the early pregnancy pregnancy reaction, so that pregnant women as much as possible intake of food to meet their nutritional needs. Light, palatable foods include a variety of fresh vegetables and fruits, soy products, fish, poultry, eggs, and a variety of cereals and products, which can be arranged appropriately according to the preferences of the pregnant woman at that time. (ii) Eat when you want to eat, eat less and more often Pregnant women with severe gestational reactions should not stick to the eating time like normal people to emphasize the regularity of the diet, not to mention the mandatory eating, and insist on eating in between vomiting. The quantity, type and time of eating should be adjusted in time according to the appetite of pregnant women. In order to increase the amount of food and ensure energy intake, we should try to adapt to the short-term changes in eating habits caused by pregnancy reactions, take care of the pregnant woman’s personal hobbies, do not unilaterally pursue the nutritional value of food, and gradually correct the situation when the pregnancy reaction stops. For general pregnancy reaction, appropriate amount of B vitamins can be supplemented under the guidance of health care doctors to reduce the symptoms of pregnancy reaction. Women in early pregnancy should pay attention to eating more vegetables, fruits, milk and other foods rich in vitamins and minerals. In order to reduce the symptoms of nausea and vomiting, eat dried bread, steamed bread, cookies, eggs and so on. (C) pay attention to supplement carbohydrates The fatty acid oxidase activity in fetal tissues is extremely low, seldom use fat for energy supply, and glucose has become almost the only source of energy for the fetus. Pregnant women can not eat at all, the body decomposition of fat ketone bodies for energy, ketone bodies on early fetal brain development will have adverse effects. Therefore, in early pregnancy, you should try to consume as much carbohydrate-rich cereals or fruits as possible, and ensure that you consume at least 150g of carbohydrates (about 200g of cereals) per day. Those who have severe vomiting and are unable to eat at all should be given glucose, vitamins and minerals intravenously under the supervision of a doctor. In order to avoid the fat decomposition of ketone bodies on the early brain development of the fetus caused by the adverse effects. （Folic acid supplementation Folic acid deficiency in early pregnancy may increase the risk of neural tube malformation and preterm delivery. Women should start planning their pregnancies by consuming as much folic acid-rich animal liver, dark green vegetables and beans as early as possible. Since folic acid supplements are better absorbed and utilized by the body than dietary folic acid, it is recommended that folic acid supplementation of 400 micrograms per day should be continued after conception and throughout pregnancy. In addition to helping to prevent neural tube malformations in the fetus, folic acid also helps to reduce the risk of hyperlipidemia in pregnancy. Good sources of folic acid are animal liver, kidney, eggs, beans, green leafy vegetables, fruits and nuts. Fifth, mid-pregnancy, the end of dietary nutrition needs from the middle of pregnancy, the fetus entered a period of rapid growth and development, and fetal growth and development, the mother’s uterus, mammary glands and other reproductive organs are also gradually developing, and the mother also needs to start for the postpartum lactation of energy as well as nutrients in reserve. Therefore, the middle and end of pregnancy need to correspondingly increase the amount of food, in order to meet the significantly increased nutrient needs of pregnant women: (a) to ensure an adequate supply of fish, poultry, eggs, lean meat and seafood Fish, poultry, eggs, lean meat is a good source of high-quality proteins, of which the fish can also provide n-3 polyunsaturated fatty acids (such as docosahexaenoic acid, DHA), which is extremely important for the development of the fetal brain and visual function. Egg yolk is a good source of lecithin, vitamin A, and vitamin B2. From mid-pregnancy onwards, you should increase the amount of fish, poultry, eggs or lean meat by 50-100 grams per day, of which fish should be eaten 2-3 times per week, and you should also eat 1 egg per day. In addition, you should eat seafood at least once a week to meet the need for iodine. (ii) Pay attention to calcium supplementation Milk or milk products are a good source of calcium, 250 ml of milk contains 260 mg of calcium, which can supplement the calcium needs of pregnant women and fetuses, and can also supplement high-quality protein. The daily calcium intake of our population is only about 400mg, far below the recommended 800mg of calcium. Mid-pregnancy: the fetus obtains 150mg of calcium from the mother every day, late pregnancy: the fetus obtains 450mg of calcium from the mother every day, and the amount of calcium in the body of the fetus at birth can reach 25-30g. In other words, during the whole pregnancy cycle, pregnant women need to supplement at least 1000mg-1200mg of calcium per day in order to ensure the needs of the mother and the fetus during pregnancy. Therefore, the Chinese Society of Nutrition recommends that the appropriate intake of calcium supplementation for pregnant women in the middle stage of pregnancy should be 1000mg/day, and the tolerable maximum intake should be 2000mg/day, while the appropriate intake of calcium supplementation for pregnant women in the late stage of pregnancy should be 1200mg/day, and the tolerable maximum intake should be 2000mg/day. From mid-pregnancy onwards, pregnant women should consume at least 250ml of milk and 300mg of calcium per day, or drink 400ml to 500ml of low-fat milk to meet the calcium needs. If, for some reason, the calcium intake from food does not meet the need, it is necessary to take calcium supplements. However, it is important to pay attention to the selection and safety of calcium supplements. Calcium supplements currently available include fine calcium carbonate, active calcium, compound calcium, etc. Studies have shown that fine calcium carbonate has a lower heavy metal content and is safer. When supplementing calcium, we should also consider the influence of the ingredients that compete with calcium in food, such as phytic acid in cereal food will form calcium phytate on calcium to affect calcium absorption, oxalic acid in some vegetables such as spinach, amaranth, bamboo shoots and calcium oxalate to form calcium oxalate may affect calcium absorption, such as spinach and tofu with the same food will form calcium oxalate may affect calcium absorption. Because milk is also rich in calcium, simply drink milk when the absorption of calcium has reached or close to the saturation range, if the calcium supplements and milk at the same time, it may cause a waste of calcium supplements. It is recommended to take both at an interval of about one hour. In addition, not smoking, drinking less alcohol and coffee are all conducive to reducing bone calcium loss. The best time to take calcium supplements is at night before bed or after meals. (c) Pay attention to iron supplementation Pregnant women are at high risk of iron deficiency anemia, and the results of the 2002 survey on the nutritional and health status of Chinese residents showed that the incidence of anemia among pregnant women in China was about 30%. The increase of maternal hemoglobin during pregnancy and the growth and development of fetus and placenta as well as the need for fetal iron reserves require timely iron supplementation. Therefore, from the mid-pregnancy to increase iron intake, more intake of iron-rich foods, such as animal blood, liver, lean meat, etc., if necessary, under the guidance of the doctor can be supplemented with a small dose of iron. At the same time, attention should also be paid to more intake of vegetables and fruits rich in vitamin C, or supplement vitamin C when supplementing iron, in order to promote the absorption and utilization of iron. (d) Ensure appropriate weight gain Maternal weight is an important indicator of maternal nutrition. Excessive weight gain during pregnancy will increase the risk of obstructed labor; too little weight gain during pregnancy, in addition to affecting the health of the mother, but also lead to fetal malnutrition and affect the health of the adult. Therefore, pregnant women should monitor their weight and adjust their food intake according to the rate of weight gain. The target value for appropriate weight gain varies according to the pre-pregnancy weight. Women whose pre-pregnancy weight is more than 20% of their ideal body weight should gain 7kg to 8kg during pregnancy, and the weekly weight gain from mid-pregnancy should not exceed 300g; women with normal pre-pregnancy weight should gain 12kg during pregnancy, and the weekly weight gain from mid-pregnancy should be 400g; women whose pre-pregnancy weight is less than 10% of their ideal body weight should aim for 14kg to 15kg during pregnancy, and the weekly weight gain from mid-pregnancy should not exceed 500g. The target value for weight gain during pregnancy is 14kg to 15kg, and the weekly weight gain from mid-pregnancy onwards is 500g. Pre-pregnancy ideal weight can be roughly estimated by the following formula, pre-pregnancy ideal weight (kg) = height (cm) – 105, pre-pregnancy ideal weight (kg) values ± 10% are normal. During this period, pregnant women should carry out low-intensity physical activities for not less than 30 minutes a day according to their own physical ability, preferably 1 ~ 2 hours of outdoor activities, such as walking, gymnastics, etc., because appropriate physical activities are conducive to maintaining the appropriate weight growth and natural delivery, outdoor activities also help to improve the nutritional status of vitamin D, in order to promote the development of fetal bones and the mother’s own bone health. To summarize, nutrition during pregnancy not only has a great impact on maternal health, but also has a direct and crucial effect on the outcome of pregnancy. Reasonable diet and balanced nutrition are the material basis for a successful pregnancy. In addition to this, a healthy lifestyle is also essential, such as abstaining from smoking and alcohol. Tobacco and alcohol have obvious toxic effects on all stages of embryonic development, such as easily causing premature labor, miscarriage, malformation and so on. Women who have the habit of smoking and drinking must abstain from smoking and alcohol during pregnancy and stay away from smoking environments.