In this piece we argue that we have reached a point at which the law on abortion in England, Scotland, and Wales makes care lesssafe and thus falls foul of the principle primum non nocere – the law is now itself a cause of harm. Our analysis focuses on a particular piece of abortion legislation, and makes proposals that are based on the contingencies of the political, regulatory and scientific contexts in which it operates. However, we also have wider concerns in examining the ‘internal morality’ of regulation in health care. The first principle of medical ethics is as pertinent to law as it is to health care practice: legal regulation should not itself be the cause of harm. This critique is independent of other questions about the morality of the activities being regulated. Thus, the arguments that we make should be accepted even by those who are opposed to abortion ‘in principle’. They are not principally arguments about abortion but about the ethics of regulation.