"[Abortion] is commonly misunderstood outside medical circles. In general terms, the word 'abortion' simply means the failure of something to reach fulfilment or maturity. Medically, abortion means loss of the fetus, for any reason, before it is able to survive outside the womb. The term covers accidental or spontaneous ending, or miscarriage, of pregnancy as well as deliberate termination. The terms 'spontaneous abortion' and 'miscarriage' are synonymous and are defined as loss of the fetus before the twenty-eighth week of pregnancy. This definition implies a legal perception of the age at which a fetus can survive out of the womb. With great advances in recent years in the ability to keep very premature babies alive, this definition is in need of revision."