Pre-conception preparation 1. Blood sugar reduction: Diabetic women with fertility requirements must strictly control their blood sugar in the first three months of pregnancy. Blood sugar should reach or be close to normal level and glycosylated hemoglobin should be controlled at less than 6% before pregnancy can be started. 2. Weight reduction: obese people should change their lifestyle and reduce their weight. 3. The following tests are recommended before pregnancy assistance: blood glucose, glycosylated hemoglobin, blood lipids, blood pressure, urine protein, fundus, neurology, electrocardiogram, and urine routine. Contraindications to assisted conception in the following cases of diabetic patients should not have children: 1. poor blood sugar control: high blood sugar of the mother can lead to an increased risk of fetal malformation, so a glycosylated hemoglobin of 7% or more is not recommended; 2. proliferative retinopathy: accelerated blood circulation in women after pregnancy, increased neovascularization and increased blood flow in the fundus will aggravate proliferative lesions in the fundus, which can lead to retinal detachment in severe cases; 3. Severe diabetic nephropathy: urine protein ≥1g/d, creatinine clearance ≤70ml/min or combined with severe hypertension, such patients are prone to intrauterine growth retardation and fetal distress after pregnancy, and mothers are prone to hyperemesis and pre-eclampsia, and are not suitable for childbirth.