Why after 50 years of effective contraception do we still have unintended pregnancy?

Unintended pregnancy is a public health concern throughout Europe. There is no common definition and no standard way to measure unintended pregnancy. Identifying unintended births is difficult and prevalence estimates vary depending on how and when the question is asked. Abortion rates are not a proxy and are themselves notoriously inaccurate. An estimated 34% (in Western Europe) to 54% (in Eastern Europe) of pregnancies are unintended. The determinants of unintended pregnancy are the length of the reproductive span and exposure to the risk of conception; the desired number of children and contraceptive use and effectiveness. The age of sexual debut fell during the 20th century in Europe to between 15 and 18 years of age. Mean age at first birth for women is now over 30 years in most European countries and most couples want no more than two children. Thus most couples must use contraception perfectly for many years in order to avoid unintended pregnancy. Use of effective contraception is high throughout most of Europe but there is scope, through better provision of sexual health services, better formal sex education and better training of providers, to increase the uptake of the most effective contraceptives and improve use of all methods. For individual women unintended pregnancy can be a disaster and recourse to induced abortion should be freely available.