after 2 years without menstruation, suddenly menstruated for 1 day at the end of august; this is a spontaneous report received from a contactable reporter(s) (consumer or other non hcp) from the regulatory authority-web. regulatory number: nl-lrb-00737741. a 52 year-old female patient received bnt162b2 (comirnaty), administration date 16jul2021 (lot number: ff0688) as dose 2, single for covid-19 immunisation. relevant medical history included: "disease risk factor" (unspecified if ongoing). the patient's concomitant medications were not reported. vaccination history included: biontech/pfizer vaccine (comirnaty) (dose 1), administration date: 11jun2021, for covid-19 immunisation. the following information was reported: postmenopausal haemorrhage (medically significant) with onset 30aug2021, outcome "recovered" (01sep2021), described as "after 2 years without menstruation, suddenly menstruated for 1 day at the end of august". reporter comment: biontech/pfizer vaccin (comirnaty) past drug therapy biontech/pfizer vaccine (comirnaty): yes date: 11jun2021 bsn (citizen service number) available: yes previous covid-19 infection: no no follow-up attempts are possible. no further information is expected.; reporter's comments: biontech/pfizer vaccin (comirnaty) past drug therapy biontech/pfizer vaccine (comirnaty): yes date: 11jun2021 bsn (citizen service number) available: yes previous covid-19 infection: no