Medical management of periconception obesity: scientific regulation of weight gain during preconception and pregnancy.

I. Weight Management During the Preconception Period for Obese Patients: Overweight and obese women have at least an 8% and 18% lower conception rate, respectively, compared to women of normal weight. Adipose tissue, as an endocrine organ, secretes factors such as leptin and IL-6, leading to insulin resistance (IR) and causing hyperandrogenemia. The degree of obesity is negatively correlated with sex hormone-binding globulin (SHBG) levels, affecting germ cell maturation and embryo implantation. Obesity has a significant impact on pregnancy and offspring, increasing the risk of gestational diabetes, preeclampsia, macrosomia, and congenital malformations. Furthermore, through epigenetic pathways, it increases the long-term risk of obesity and cardiovascular disease in offspring, a phenomenon known as "metabolic programming." Recommendations for preconception management:

Assess physical health status, including menstruation, blood lipids, blood sugar, sex hormones, and gynecological ultrasound.

Psychological and behavioral interventions: guide the public to correctly understand the risks of obesity to mothers and infants, and encourage the establishment of food diaries.

Medical nutrition therapy: Achieve a negative energy balance of 30% or 500-750 kcal daily. Replace saturated fatty acids with unsaturated fatty acids and consume plenty of fiber. Individualized choices include CRD, HPD, and intermittent fasting.

Physical activity: at least 150 minutes of aerobic exercise per week, of which 90 minutes should be of moderate to high intensity.

Medication and Surgery: If ineffective, orlistat or metformin may be considered (especially for PCOS patients). Surgery should be considered for patients with lifestyle and medication interventions that have failed and a BMI ≥ 35 kg/m² with high-risk comorbidities. It is recommended to maintain a balanced diet for 1-2 years after surgery before conceiving. II. Weight Management During Pregnancy for Obese Patients

Risk assessment: A mother's BMI > 30 kg/m² is considered a high-risk pregnancy. The offspring are more likely to experience intrauterine distress and hypoglycemia, and the mother has an increased risk of cesarean section and postpartum type 2 diabetes.

Recommended weight gain during pregnancy: ◇ BMI 25-29.9 kg/m²: 0.52 kg in early pregnancy, 0.23-0.32 kg/week in mid-to-late pregnancy, total weight gain 6.8-1.4 kg over the entire pregnancy. ◇ BMI ≥ 30 kg/m²: 0.52 kg in early pregnancy, 0.18-0.27 kg/week in mid-to-late pregnancy, total weight gain 5.1-9.1 kg over the entire pregnancy.

Dietary recommendations: Avoid added sugar and excessive fat. Limit fruit intake to 200-350g per day, and replace dairy products with low-fat or fat-free options. If weight gain is rapid, choose more fish.

Exercise: If there are no obstetric contraindications, pregnant women in the second and third trimesters should engage in appropriate moderate-intensity activities every day, such as brisk walking, swimming, or prenatal yoga.