Abortion (gabbhapàtana) is a form of birth control where the foetus is killed to prevent it from developing fully and being born. Abortion was known in ancient India and was done either by an operation, by violently shaking the mother or by administering various drugs. According to Buddhism, life begins at conception or very soon afterwards and thus abortion is considered to be killing. Monks and nuns are forbidden to procure abortions for others (Digha Nikaya 1.11). In some cases abortion may be necessary to save the life of a mother but today most abortions are performed to avoid embarrassment or the inconvenience of a baby arriving unplanned. To the Buddhist, these seem to be very poor reasons for destroying a life. Abortion is illegal in Sri Lanka and Burma, but not in Thailand.
Buddhism and Abortion, Damien Keown, 1999.