This article explains how the strategic use of public health evidence, showing that criminalisation of abortion does not result in lower abortion rates, is changing the way judges are confronting constitutional challenges to abortion regulations. The state may have a legitimate interest - and in some legal systems, a duty - to protect prenatal life. Nevertheless, courts are upholding regulations liberalising abortion and declaring criminalisation regimes unconstitutional. This is possible given that lower abortion rates are not achieved through criminalisation, but through preventive policies. In addition, courts uphold liberalisation when the infringement of women's rights resulting from criminalisation outweighs its purported benefits. This new legal narrative has been developed during the last decades by a series of court decisions in Europe and Latin America, and may prove useful for legal advocacy in some countries in Africa. The narrative combines the use of an analytical framework called the proportionality principle with an interpretation of constitutional rights that draws from gender-sensitive international human rights standards and factual evidence about the effects of criminalisation on women's lives and health.