Post pill amenorrhoea--how much of a problem?

Presumably, post-Pill amenorrhoea reflects a mechanism whereby a hypothalamus "switched off" by the Pill does not switch on again when therapy is stopped. In Australia the incidence of post-Pill amenorrhoea appears to be in the vicinity of 1 in 200 for a six months duration and 1 in 400 for over 12 months. The only clearly defined feature of women who are likely to develop the syndrome is previous cycle irregularity--cycles consistently longer than 35 days. There is indication that nullipara and women with gross weight fluctuation may also be more likely to be affected. In management, skull X-ray is mandatory and if galactorrhoea is present, serum prolactin can be of diagnostic importance. Otherwise, the deciding factor is whether there is a desire or not for pregnancy.