Do plain plastic and copper bearing intrauterine contraceptive devices have a central mechanism of action?

The notion that the intrauterine contraceptive device (IUCD) has a central, as well as a local action, is examined. Although the IUCD undoubtedly has a local action, certain IUCD related side effects, e.g. galactorrhoea, bloating and premenstrual syndrome and inadequate luteal function can be explained if the IUCD has some central action. The powerful postcoital anti-fertility effect of both copper-bearing and plain plastic IUCDs probably also depends to some extent on a central action. The central action of the IUCD is probably due to initiation of reflex hypothalamic activity following intrauterine reflex stimulation. The hypothalamic response to IUCD insertion consists of release of beta-endorphin accompanied by raised levels of prolactin, vasopressin and oxytocin.