heaviness of the bleeding; heaviness of the bleeding and severity of cramps; heaviness of the bleeding and severity of cramps; heavy one day and then just spotting the next. I continued having irregular bleeding like this for nearly 2 weeks; fatigue; 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 15Dec2021 18:45 (Lot number: FF8839) at the age of 29 years as dose 3 (booster), single for covid-19 immunisation. Relevant medical history included: "known allergies: Penicillin" (unspecified if ongoing); "known allergies: latex" (unspecified if ongoing); "Dysmenorrhea", start date: Oct2012, stop date: Feb2021, notes: Symptoms subsided after Nexplanon implantation; "Depression" (unspecified if ongoing); "ADHD" (unspecified if ongoing); "my periods, as well as pain from cramps and body aches" (unspecified if ongoing); "my periods, as well as pain from cramps and body aches." (unspecified if ongoing). Family history included: "Anemia", start date: Oct2012, stop date: Apr2021, notes: Managed with birth control confirmed not present at last physical, Mother has a history of anemia. Concomitant medication(s) included: ESCITALOPRAM; DEXTROAMPHETAMINE HYDROCHLORIDE; NEXPLANON taken for dysmenorrhoea, anaemia, start date: Feb2021 (ongoing); 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: Comirnaty (Dose Number: 1, Batch/Lot No: EN6203, Location of injection: Arm Left, Vaccine Administration Time: 12:45 PM, Route of administration: Intramuscular), administration date: 24Feb2021, when the patient was 28 years old, for COVID-19 immunization; Comirnaty (Dose Number: 2, Batch/Lot No: EN6205, Location of injection: Arm Left, Vaccine Administration Time: 02:00 PM, Route of administration: Intramuscular), administration date: 16Mar2021, when the patient was 28 years old, for COVID-19 immunization, reaction(s): "Initial onset of heavier menstruation was after second vaccine period began early Apr2021", "my periods for the following 2 months were heavier and more painful", "PMS". The following information was reported: HEAVY MENSTRUAL BLEEDING (non-serious), outcome "recovered" (03Jan2022), described as "heaviness of the bleeding"; DYSMENORRHOEA (non-serious) with onset 19Dec2021 10:00, outcome "recovering", DISEASE RECURRENCE (non-serious), outcome "recovering" and all described as "heaviness of the bleeding and severity of cramps"; MENSTRUATION IRREGULAR (non-serious) with onset 18Dec2021, outcome "recovering", described as "heavy one day and then just spotting the next. I continued having irregular bleeding like this for nearly 2 weeks"; FATIGUE (non-serious) with onset 18Dec2021, outcome "recovered", described as "fatigue". Therapeutic measures were not taken as a result of heavy menstrual bleeding, dysmenorrhoea, disease recurrence, menstruation irregular. Additional information: if other vaccine in fourweeks: No. If covid prior vaccination: No.If covid tested post vaccination: No. Relevant tests: None. Specific relevant tests: None. Clinical Course: She was not certain that this is a true adverse event. She had a Nexplanon implant because wanted to reduce and hopefully eliminate my periods due to excessive pain. She have not had a period since September 2021. After receiving my booster shot of Comirnaty on Thursday, she began experiencing cramps, and then today my period has begun. She wanted to also note that when received second shot in March 2021, she was still experiencing regular periods, but they became heavier and more painful for 1-2 months following the shot. Initial onset of heavier menstruation was after second vaccine period began early Apr2021. At this point she had the nexplanon implant for more than a year and it was effective at reducing the heaviness of 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 were heavier and more painful, though not to the same degree as they have been before I received nexplanon. Following this, her periods became very light again and infact she had not had a period since Sep2021 prior to her experience in Dec. She received booster on 15Dec2021, and in the 3 days following and experienced a great deal of fatigue (which expected) but also began to get progressively was very unusual -heavy one day and then just spotting the next. She continued having irregular bleeding like this for nearly 2 weeks - ceased 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.  No follow-up attempts are possible. No further information is expected.; Sender's Comments: Linked Report(s) : US-PFIZER INC-202101823556 same patient/drug, different event, different dose