Abortion is the ending of pregnancy by the removal or forcing out from the womb of a fetus or embryo before it is able to survive on its own. An abortion can occur spontaneously, in which case it is often called a miscarriage. It can also be purposely caused in which case it is known as an induced abortion. The term abortion most commonly refers to the induced abortion of a human pregnancy. The similar procedure after the fetus may be able to survive on its own is medically known as a "late termination of pregnancy". Modern medicine uses medications or surgical methods for induced abortion. The two medications mifepristone and prostaglandin are as effective as a surgical method in the first trimester. While the use of medications may be effective in the second trimester, surgical methods appear to have a lower risk of side effects. Birth control, including the pill and intrauterine devicess can be started immediately after an abortion. Abortion in the developed world has a long history of being among the safest procedures in medicine when allowed by local law. Uncomplicated abortions do not cause either long term mental health or physical problems.