bleeding menstrual heavy; this is a spontaneous report received from a contactable reporter(s) (consumer or other non hcp) from the regulatory agency (ra). other case identifier(s): gb-mhra-vac-202202130842073300-0i1ov (ra), gb-mhra-adr 26598288 (ra). a female patient received bnt162b2 (comirnaty) (batch/lot number: unknown) as dose number unknown, single for covid-19 immunisation. the patient's relevant medical history and concomitant medications were not reported. the following information was reported: heavy menstrual bleeding (medically significant) with onset 17dec2021, outcome "not recovered", described as "bleeding menstrual heavy". the event "bleeding menstrual heavy" was evaluated at the physician office visit. clinical course: the patient was referred to gynaecology by general practitioner (gp) as bleeding has not resolved after 3 months. the reaction did not occur as a result of a mistake made in the administration of the vaccine. no follow-up attempts are possible; information about lot/batch number cannot be obtained. no further information is expected