Rates of teenage pregnancy in the USA are high by comparison with those in other industrialised countries, but have fallen by 30% in the past decade, from a peak of 117 per 1000 in 1990, to 82 per 1000 in 2001.
Some studies have suggested that most of the reduction results from increased uptake of abstinence, most from increased use of reliable methods of contraception; some from both equally, whereas others provide evidence that changes in economic factors are responsible, notably the welfare reforms introduced by the Clinton administration.
— The Lancet