Background

In the 1980s, the term ‘contragestion’ was coined by French scientists investigating progesterone receptor modulators (PRMs). Contragestion refers to a method that works after ovulation and throughout luteal phase and beyond.1 A contragestive could prevent or disrupt implantation, which may be politically controversial. On the other hand, a strategy to avoid abortion has been the concept of ‘menstrual regulation’ which is widely practised in some parts of the world. Thus, the mechanism of action may be less important than how we name the method to get through political and regulatory constraints and psychosocial barriers.

In the 21st century, the status quo of existing contraceptive choice is not sufficient. Despite a range of contraceptive methods, hormonal and non-hormonal, and various delivery systems and durations of action, we still have high rates of unintended pregnancy. No method of contraception is 100% effective. Also, not all women will want to use a method that constantly releases hormones or have a device present in the body even if it is highly effective and reversible. Uptake of existing methods of contraception is also limited due to experienced or feared side effects. Some women may want an occasional-use method only. While emergency contraception (EC) pills can be used as an occasional method or pericoital method, they are only of limited …