Demographic effects of the introduction of steroid contraception in developed countries.

The use of the contraceptive pill increased very rapidly in the 1970s in many developed countries, and fertility almost simultaneously started to decline. We discuss here the possibility of a causal link between these two major changes. We first provide evidence for a relationship between the spread of oral contraceptive use and the change in fertility in many European countries over the last three or four decades. The situation of specific countries is examined more in depth on the basis of available literature. We then review the various theories attempting to explain these trends and see how the family planning variables are treated in these approaches. At the country level, the conclusion is unambiguous: within individual countries, there is no systematic negative correlation between fertility and contraceptive pill use. The development of hormonal contraception cannot be considered as responsible for either starting or the size of the fertility decline. A more subtle chain of causality must be considered, but there is no agreement on a general theory of fertility changes. Most authors, however, agree that the diffusion of modern contraception has certainly contributed to the reduction in the number of unwanted pregnancies and has also facilitated and favoured the adoption of new (more restrictive) norms for the ideal family size.