Assisted reproductive technology (ART) are methods used to achieve pregnancy by artificial or partially artificial means. It is reproductive technology used primarily for infertility treatments, and is also known as fertility treatment. Some forms of ART are also used with regard to fertile couples for genetic reasons (preimplantation genetic diagnosis). ART is also used for couples who are discordant for certain communicable diseases; for example, AIDS to reduce the risk of infection when a pregnancy is desired. Examples of ART include in vitro fertilization, intracytoplasmic sperm injection (ICSI), cryopreservation and intrauterine insemination (IUI). There is yet no strict definition of the term ART; its usage mainly belongs to the field of reproductive endocrinology and infertility.