was still experiencing regular periods, but they became heavier and more painful for 1-2 months following the shot; was still experiencing regular periods, but they became heavier and more painful for 1-2 months following the shot; pain from cramps; body aches; PMS; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 29 year-old female patient (not pregnant) received bnt162b2 (BNT162B2), intramuscular, administered in arm left, administration date 16Mar2021 14:00 (Lot number: EN6205) at the age of 28 years as dose 2, single for covid-19 immunisation. Relevant medical history included: "Known allergies: Penicillin and latex" (unspecified if ongoing), notes: Known allergies: Penicillin and latex; "Known allergies: Penicillin and latex" (unspecified if ongoing), notes: Known allergies: Penicillin and latex; "Dysmenorrhea", start date: Oct2012, stop date: Feb2021, notes: Symptoms subsided after Nexplanon implantation; "ADHD" (unspecified if ongoing); "Depression" (unspecified if ongoing). Family history included: "Anemia", start date: Oct2012, stop date: Apr2021, notes: Managed w/birth control confirmed not present at last physical, Mother also has a history of anemia. Concomitant medication(s) included: ESCITALOPRAM; LEXAPRO taken for depression, start date: Nov2020, stop date: Dec2021; ADDERALL taken for attention deficit hyperactivity disorder, start date: Aug2021, stop date: Dec2021. Vaccination history included: Bnt162b2 (Prev dose product: COVID 19,, Prev dose brand: Comirnaty,, Prev dose brand unknown: False,, prev dose lot number: EN6203, Prev dose lot unknown: False,, Prev dose administration date: 24Feb2021,, Prev dose administration time: 12:45 PM, Prev dose dose number: 1,, Prev dose vaccine location: Left arm, 1st Dose, Date: 24Feb2021, Time: N/A, Anatomical site of injection: left arm, Route of administration: Intramuscular, Batch/Lot number: EN6203), administration date: 24Feb2021, when the patient was 28 years old, for Covid-19 Immunization. The following information was reported: HEAVY MENSTRUAL BLEEDING (non-serious) with onset Apr2021, outcome "recovering", DYSMENORRHOEA (non-serious), outcome "recovering" and all described as "was still experiencing regular periods, but they became heavier and more painful for 1-2 months following the shot"; DYSMENORRHOEA (non-serious) with onset 21Mar2021, outcome "recovered", described as "pain from cramps"; PAIN (non-serious) with onset 21Mar2021, outcome "recovered", described as "body aches"; PREMENSTRUAL SYNDROME (non-serious) with onset 21Mar2021, outcome "recovered", described as "PMS". Therapeutic measures were taken as a result of heavy menstrual bleeding, dysmenorrhoea, dysmenorrhoea, pain.  Additional information: Most recent dose details: Product: COVID 19, Brand: Comirnaty, Brand unknown: False, Lot unknown: FF8839, Administration date: 15Dec2021, Administration time: 06:45 PM, Dose number: 3,Vaccine location: Left arm, Route of administration: Intramuscular. No other vaccine was administered in four weeks. Other medications in two weeks included Dextroamphetamine salts. Patient was not certain that this was a true adverse event. She have a Nexplanon implant because she wanted to reduce and hopefully eliminate her periods due to excessive pain. She have not had a period since Sep2021. After receiving her booster shot of Comirnaty on Thursday, she began experiencing cramps, and then today her period had begun. She wanted to also note that when she received her second shot in Mar2021, she was still experiencing regular periods, but they became heavier and more painful for 1-2 months following the shot. Patient did not had covid prior to vaccination. Patient was not tested for covid post vaccination. Booster recommended by CDC/local government. Relevant Tests were reported as None. Specific Relevant Test For Thromboembolic Events with Thrombocytopenia was reported as None. AE Term: 14 days, Onset Date on 18Dec2021, Not serious with Outcome: Recovered. AE Term: 2 cycles, Onset Date: 21Mar2021, Not serious, Outcome: Recovered. Event did not require the initiation of new medication/other treatment/ procedure. Initial onset of heavier menstruation was after second vaccine period began early Apr2021. At this point patient had the Nexplanon implant for more than a year and it was effective at reducing the heaviness of her periods, as well as pain from cramps and body aches she came to associate with menstruation and PMS. Following vaccination, her periods for the following 2 months more heavier and more painful. though not to the same degree as they have been before she received Nexplanon. Following this, her periods became very light again, and in fact she had not had a period since Sep2021 prior to her experience on Dec. She received her booster on 15Dec2021, and in the 3 days following she experienced a great deal of fatigue (which she expected) but she also began to get progressively more intense cramps, until she discovered she was bleeding on 18Dec2021. It was very unusual- heavy one day and then just spotting the next. She continued having irregular bleeding like this for nearly 2 weeks- easier the week- of 03Jan2022. The heaviness of the bleeding and severity of cramps again were not as extreme as they had been prior to receiving Nexplanon  Follow-up attempts are completed. No further information is expected.; Sender's Comments: Linked Report(s) : US-PFIZER INC-202101814786 same patient/drug, different event, different dose