From 12 weeks of gestation to delivery, renal blood flow and glomerular filtration rate can increase by 30%-50%. The long diameter of the kidney can increase by 1 cm and return to normal within 6 months after delivery. Pregnancy can aggravate the existing kidney disease due to the changes in kidney physiology. So under what conditions is pregnancy allowed in women of childbearing age with kidney disease? The conditions that allow pregnancy are: 1. normal kidney function; 2. normal blood pressure; 3. proteinuria does not reach the category of nephropathy. In patients with chronic renal insufficiency, moderate to severe decline in renal function, pregnancy is prohibited in the first place. And once the pregnancy is unintentional, measures should be taken to terminate the pregnancy, otherwise it will cause deterioration of renal function and irreversible. In patients with mild renal impairment, blood pressure, renal function, and urine protein should be closely observed, and pregnancy should be terminated if there is a large amount of proteinuria, hypertension, and a 20%-30% decrease in renal function compared to before. In patients with chronic nephritis, during pregnancy, there is an increase in urine protein without changes in renal function and blood pressure can be controlled in the normal range, pregnancy can be continued while closely observing changes in the condition. If proteinuria of the nephrotic range, i.e., 24-hour urine protein > 3.0 g, glucocorticoid therapy should be administered. For lupus nephritis common in women of childbearing age, pregnancy must control lupus activity for more than 6 months with normal renal function and blood pressure. Close observation of autoantibodies should be strengthened after pregnancy, especially the detection of anticardiolipin antibodies. If the titer is high, eclampsia may occur and the pregnancy should be terminated depending on the situation. In conclusion, renal patients during pregnancy should be closely followed up with urinalysis, renal function and blood pressure. Once declining renal function is detected, reversible factors, such as dehydration and urinary tract infection, should first be excluded and removed. If there are no such factors but the renal function is deteriorating, termination of pregnancy should be considered.