Pregnancy has generally been regarded as very high risk in women with chronic renal insufficiency. In this review, we describe the physiologic changes in systemic and renal haemodynamics during pregnancy, as well as the nature and severity of possible maternal and foetal complications in the setting of underlying renal disease. The risks are proportional to the degree of functional renal impairment, the presence or not of proteinuria and/or arterial hypertension at the time of conception, and are related to the type of underlying nephropathy or systemic disease in the mother. Furthermore, if the renal disease has been diagnosed before pregnancy, a better planning of the moment of conception, as well as a tight follow-up, allow for a better maternal and obstetrical outcome.