irregular periods; Got period again; Arm was a little sore; This is a spontaneous report from contactable consumer. This 44-year-old female patient reported for herself that she received her first dose of BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection, Batch/Lot number: EW0177, Expiry date: 31Aug2021) via an unspecified route of administration into the right arm on 06Jun2021 (at the age of 44-year-old) as single dose for COVID-19 immunisation. The patient medical history and concomitant medications were not reported. The patient received her second dose of BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection, Batch/Lot number: UNKNOWN, Expiry date: 30Sep2021) via an unspecified route of administration into the right arm on 30Jun2021 at 11 AM as single dose for COVID-19 immunisation. No prior vaccinations within 4 weeks. On an unspecified date, the patient experienced irregular periods. 0n 06Jun2021, her arm was a little sore and on 24Jun2021, she got periods again. Within 4-5 hours after vaccination, the right arm was getting sore, later in the evening there was minor soreness. She knew that the second shot would be worse. She was able to deal with the discomfort through the night. That day, her right arm was visibly pulsating and twitching.  She explains that she can move her arm halfway up freely, otherwise if she moves it up any further the pulsating was worse. Pain really was not an issue. She has experienced irregular periods since her first dose of the Pfizer Covid 19 vaccine. She has had two periods in a month since her first dose Jun2021. Referred to HCP for continued evaluation and treatment. She reported that the first dose of the Covid-19 vaccine was totally fine. Later, in the evening before going to bed, her arm was a little sore.  It was nothing major and went away the second day. On 01Jul2021, obviously her arm was still sore, but now a throbbing was happening and inquired if that was normal. If she just puts her arm down, her arm was almost pulsating like a heart. The pulsating was not hurting, it was just weird. The reason that she waited a few days before getting the second dose of the Covid-19 vaccine is because she got her period twice in Jun2021. She had her period on 01Jun2021 and then got the shot on 05Jun2021 and her period was over.  Then she got her period again in Jun2021 and that never happens to her. She got her period on 24Jun2021 again and said that she was not going to be on her period getting the second Covid-19 shot. Her period completed on 28Jun2021, but she waited until 30Jun2021 to get the second dose of the Covid-19 vaccine. The patient was taking Pfizer Covid-19 vaccine to protect her family. Outcome was unknown for event irregular periods. Outcome was resolved for events arm was a little sore on 07Jun2021 and got period again on 28Jun2021.  Caller reported that a couple of hours after receiving the second dose of the Covid-19 vaccine, immediately after 4-5 hours, she felt the shot in her arm. She still has soreness in her arm.  With the soreness, it kind of hurts to move her arm but it was nothing excruciating.  She could not really lift her arm up high or anything, but it was getting better. Arm was throbbing: It was pulsing even her child can see it and it just started happening and had never seen anything like that. She needed to call somebody because that was just weird.  Follow up(01Jul2021): This is a follow up spontaneous report from contactable consumer. This 44- years- old female (Patient) reported for herself which included product details.  Additional information has been requested.