Intermenstrual bleeding (IMB) refers to vaginal bleeding (other than postcoital) at any time during the menstrual cycle other than during normal menstruation. It can sometimes be difficult to differentiate true IMB bleeding from metrorrhagia (irregularly frequent periods).
This is a companion discussion topic for the original article at https://patient.info/doctor/gynaecology/intermenstrual-and-postcoital-bleeding