Heavy period with clots; Chest pain; Bleeding between periods with clots; Heavy period with clots; This is a spontaneous report from a contactable physician via Medical Information Team. A 36-years-old female patient (daughter) received BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection), via an unspecified route of administration on an unspecified date in 2021 as a dose 1, single for COVID-19 immunisation. The family medical history relevant to AE(s) was reported as none. The patient's medical history (including any illness at time of vaccination) included ongoing problems with having an arrhythmia, has premature beats and ongoing mitral valve prolapse. The patient's concomitant medication was reported as she takes a beta blocker, but name of beta blocker was unknown to the caller. History of all previous immunization with the Pfizer vaccine considered as suspect was reported as this was the first dose. Additional vaccines administered on same date of the Pfizer suspect was reported as none. Prior vaccinations (within 4 weeks) were reported as none. The AE(s) following prior vaccinations were reported as none. It was reported that, does not know when the patient received first dose, assuming in shoulder, but does not know which one. Stated that, it was about two months ago and patient only received one dose. The caller on the line called about the COVID vaccine. He was called to tell about what happened to his daughter after she got the vaccine and wondered whether this has happened with other people. Stated that, this was occurred after the first dose. Initially, two weeks after the first dose or maybe a little longer after that his daughter had chest pain, it subsided, but it did occur off and on. However, he does not know the start date. The chest pain gradually subsided over a period of time. Also, between periods she had bleeding with clots, started a week or so after the vaccine. Then, her next period was a heavy period with clots which subsided. Confirmed it was just the one period. Stated that, she was fine now. The caller stated that, he does not have full details regarding event or his daughter's vaccine. The reporter considered all the events as serious (medically significant). The events did not require a visit to emergency room and physician office. The relatedness of drug to all the reaction(s)/event(s): Reactions assessed: Chest pain, Bleeding between periods with clots, Heavy period with clots, Source of assessment: Primary Source Reporter, Method of assessment: Related. The outcome of the events for chest pain was recovering while for the other events was recovered completely on an unspecified date in 2021. Later stated or 99 % recovered completely.  Information about lot/batch number has been requested.; Sender's Comments: Based on the close temporal association there is possibility of causal association between the events reported and the suspect drug BNT162B2. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate.