Pre-pregnancy obesity standard can be measured by body mass index (BMI), according to the weight (KG) divided by the square of height (M) (BMI = kg/m^2)) to calculate the individual BMI value. With BMI=22 as the base, between 18.5-24 is the standard weight; below 18.5 is underweight; above 24 is overweight; if BMI exceeds 27, it is obese. In addition, waist circumference and body fat percentage can also be used as assessment tools. If the male waist circumference is greater than 90 centimeters, female waist circumference is greater than 85 centimeters, belongs to obese; if 30 years old or more male body fat rate is greater than 25%, female body fat rate is greater than 30%, even if the weight is not heavy, waist circumference is not large, also belongs to obese groups. A, pre-pregnancy obesity affects pregnancy 1, pre-pregnancy obesity on the impact of pregnancy Pre-pregnancy obese women are likely to lead to pregnancy and medical complications, such as gestational diabetes, hypertension, pre-eclampsia, venous embolism, phlebitis, anemia, nephritis, gestational weeks more than forty-two weeks, labor contraction weakness occurred in difficult labor, the opportunity to increase the need for cesarean section. In the process of caesarean section, the common complications for obese women are large amount of bleeding, prolonged opening time and increased chance of post-operative infection, especially for very obese people (body mass index more than 40), pain-relieving anesthetic drugs are very sensitive to their respiratory depression. 2, the impact of pre-pregnancy obesity on the fetus Previous studies have shown that pre-pregnancy obese women are more likely to have fetal birth defects than normal weight people, but also increase the risk of fetal macrosomia, postnatal hypoglycemia, perinatal fetal mortality are significantly higher than the general pregnant women. According to the data, women who are overweight before pregnancy are prone to metabolic abnormalities, resulting in abnormalities in the development of the embryonic nervous system, and are twice as likely to have a child with neural tube abnormality as those with normal weight; women who are overweight after pregnancy are four times more likely to have a child with neural tube abnormality than those with normal weight. For example, the risk of fetal spina bifida was more than three times higher in women who were obese before pregnancy than in the normal weight group, the risk of cardiac malformation was twice as high as in the control group, and the risk of abdominal wall malformation umbilical bulge was more than three times higher than in the control group. Other newborn congenital defects related to the mother’s pre-pregnancy obesity include heart, anus, limbs, septum and belly button, etc. 3, pre-pregnancy obesity will cause infertility Australian Adelaide University researchers Cardons Mingle found that a protein in the cells around the egg to provide nutrients for it is the key to linking obesity and infertility, obese women are not easy to get pregnant because they expel the egg conception into a healthy embryo is less likely, women overweight will affect their ovulation, the ability to conceive and the fetus If a woman is obese due to endocrine disorders before pregnancy, she is prone to polycystic ovary syndrome, which makes it difficult for follicles to mature and affects normal ovulation, resulting in infertility. Studies have found that if both men and women are obese, they are three times more likely to wait more than a year to become pregnant than a normal weight couple. Even if both men and women are overweight, but have not yet reached the degree of obesity, they wait a year before the woman can conceive the odds are 1.4 times higher than the couple with normal weight. 4, the impact of male preconception obesity male overweight or obese people exist low testosterone levels, poor sperm quality, fertility decline and other phenomena. Studies have shown that obese men have more poor quality sperm compared to men with normal waist circumference, and the risk of infertility will increase by 10% for every increase of about 9 kg beyond the weight. Why does obesity affect the quantity and quality of a man’s sperm? First, adipose tissue has the characteristic of turning androgen into estrogen, which makes androgen decrease and estrogen increase relatively in men’s body, which hinders sperm production and affects sperm quality. Secondly, the normal body temperature of human body is about 37℃, while the optimal temperature for sperm production is 2℃ lower than the normal temperature. Because obese men have more fat, and therefore higher body temperature than normal, the temperature of their groin and scrotum area is likely to rise, which will directly affect the spermatogenic ability of the testes, resulting in reduced sperm production, even if the number of sperm generation is not affected, but the quality of the sperm generated will also be affected. Third, male obesity easily affects the testicles, penis and other reproductive system development, obese people are prone to induce hypertension, diabetes, such diseases can cause sexual dysfunction. According to the body mass index (BMI) will be divided into different groups of these men, BMI between 20 to 25 for normal weight, 25 to 29 for overweight, 30 and above for obese. The results of the study showed that men with a BMI of 20-25 had higher levels of normal sperm, while the overweight and obese not only had less semen volume (sperm count), but also had less normal sperm. Obese men have more than 60% chance of having less sperm and their chance of having abnormal sperm is more than 40%. The situation is similar for overweight people and obese men. Other factors that may affect the sperm count, such as smoking, alcohol consumption, drug abuse and age, confirm that obesity does affect sperm quantity and quality. Second, pre-pregnancy obesity diet regulation Most pre-pregnancy obese people lack good habits, such as moderate exercise, healthy low sugar, low salt, low oil, high fiber diet, etc.. It is recommended that obese people are best to lose weight before pregnancy, from diet and exercise to control weight to normal BMI values. Third, pre-pregnancy obesity need to change First, reasonable arrangements for daily meals, the formation of healthy, scientific eating habits. On the basis of the balance of dietary nutrients to reduce the total daily calorie intake and reduce the formation of excess fat. The principle is low energy, low fat, suitable for high-quality protein (such as fish, eggs, soybean products, chicken, milk, etc.) and the proportion of calories provided by carbohydrates, protein and fat is 60% to 65%, 15% to 20%, 25%, respectively, to reduce fat (such as fatty meat, offal, egg yolk, nuts, vegetable oil, etc.) is the main. Regularly do a good job of daily staple foods, vegetables and fruits with the right meal table, eat less and more meals, each meal can be seven or eight minutes full, do not overeat, need to chew and swallow slowly to extend the eating time. Try to pick high-fiber, low-fat food, but also before the meal can eat light vegetable soup to increase satiety and reduce appetite. Second, to strengthen sports and exercise. Sports and exercise to medium and low intensity exercise is appropriate, because the muscle oxygen consumption increased, a few hours after exercise oxygen consumption is still greater than when quiet, and than strenuous exercise is easy to adhere to, such as brisk walking, jogging, playing badminton, playing table tennis, dancing, swimming and so on. Warm tips Obese friends must lose weight in advance if they plan to prepare for pregnancy in the future. Because a slim body reflects a healthy state of life. If it is a heavy obese people (BMI ≥ 32.5) for pregnancy and weight loss surgery, it is recommended to take contraceptive measures within one year.