Fetal growth retardation is at present the major obstacle for further reduction in preterm births. After 25 years of continuous decline in the preterm birth rate in France from 6.9% in 1972 to 4.4% in 1981 and 3.8% in 1989, there has been an increase to 4.5% in 1995. The major new fact is the progressive increase of medically induced preterm births, mostly related to fetal growth retardation. Spontaneous preterm births have continued to decrease throughout all these years.