The effect of chronic nephritis on the fetus in late pregnancy depends on the degree of renal damage. Clinically, those with proteinuria have swelling without hypertension and normal renal function, and about 30% have hyperemesis, and the fetus has a better prognosis. In the case of hypertension, proteinuria and hypertension are the main manifestations, and renal function is normal, but the pregnant women are prone to hyperemesis during pregnancy, with early and severe symptoms and impaired renal function, and higher perinatal fetal mortality. Pregnant women with combined renal insufficiency have proteinuria, hypertension and significant renal failure, which is extremely detrimental to the prognosis of the pregnant woman and the fetus, and even life-threatening. Because pregnancy causes an increase in systemic blood flow, increased permeability of glomerular capillaries, and an increase in glomerular filtration rate, essentially by more than 50% compared to normal, physiological proteinuria can occur. The burden on the kidneys is further increased in late pregnancy. When pregnancy is combined with chronic nephritis, it can affect the blood flow of uterine vessels and uterine placenta, and the placenta undergoes corresponding pathological changes, which can easily lead to pathological proteinuria and hypertension, and the increase of blood pressure in the later stage can easily lead to pre-eclampsia and eclampsia, and fetal death in the uterus, and it can also lead to placental abruption due to hyperemesis, which can easily lead to preterm labor and miscarriage.