[{"from": "human", "value": "Provide a brief overview of this molecule. [C][C][C@][C][C][C@H1][C@H1][Branch1][=C][C@@H1][Ring1][=Branch1][C][C][C@][Ring1][=Branch2][Branch1][Ring1][C][#C][O][C][C][C][=C][C][=Branch1][C][=O][C][C][C@H1][Ring2][Ring1][C][Ring1][#Branch1]"}, {"from": "gpt", "value": "The molecule is a synthetic progestogen similar to [Progesterone] used in contraception and hormone therapy. Also known as Plan B, it is used as a single agent in emergency contraception, and as a hormonal contraceptive released from an intrauterine device, commonly referred to as an IUD. Some of these devices are known as Jaydess, Kyleena, and Mirena.  A subdermal implant of levonorgestrel that slowly releases the hormone over a long-term period is also available.  In addition to the above uses, levonorgestrel is used as a component of long-term combination contraceptives.   Globally, levonorgestrel is the most commonly used emergency contraceptive. It was initially granted FDA approval in 1982 and was the first emergency contraceptive containing only progesterone, showing high levels of efficacy and a lack of estrogenic adverse effects when compared to older emergency contraceptive regimens."}]