Pregnancy and kidney disease: from medicine based on exceptions to exceptional medicine.

The Webster dictionary defines exception as an anomaly, a person or thing that does not follow a rule, while the adjective exceptional has a different nuance, and means "above average". These two words may describe how obstetric nephrology has shifted from the description of very rare cases, to the development of a complex new and fascinating branch of medicine, that counterbalances obstetricians' usually optimistic outlook by focusing on subtle challenges posed by chronic diseases, and mitigate the frequently grim approach of nephrologists, with a message of hope: women with kidney disease can have the same basic life goals as healthy women their age. Although studies relating to kidney disease in pregnancy are being published more frequently, not all questions have been considered or answered, and clinicians are often challenged by a lack of detailed information and practical guidelines. Thus in this complex, difficult, but also fascinating and evolving panorama, the Journal of Nephrology is publishing a issue dedicated to obstetric nephrology, in an attempt to contribute to the development of this field, with the specific aim of offering practical insights and critical contributions capable of helping clinicians in the management of these "exceptional exceptions".