A low birth weight (LBW, < 2500 g), intrauterine growth restriction (IUGR), and preterm birth (PB, < 37 weeks of gestational age) are the most common clinical factors for an altered programming of nephron number and are associated with a greater risk for hypertension, proteinuria, and kidney disease later in life. At present, an indirect assessment of total nephron number based on postnatal markers is the most important approach to evaluate the risk for future kidney disorders in newborn infants with a LBW, IUGR or PB. Here we describe advances made in animal experiments and biochemical markers in humans, and the recommendations for the prevention of preconception kidney injury, including social factors and chronic diseases. According to the evidence, IUGR and prematurity alone can modulate nephrogenesis and kidney function, and, if occurring simultaneously, their effects tend to be cumulative.