endometriosis; fibroids; I recently received my Covid vaccine and about a month later had a hospitalization due to abnormal uterine bleeding; This is a spontaneous report from a contactable consumer (patient). A 35-year-old female patient received her second dose of BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE; lot number: EN5318, expiration date not reported), via an unspecified route of administration on 07Feb2021 09:00 (at the age of 34-years-old) at 2nd dose, single in the left arm for COVID-19 immunisation. Medical history included two C-sections (patient was over a year post-partum from having her last child). Concomitant medication included citalopram hydrobromide (CELEXA) for anxiety from Apr2020 to an unspecified date at 10mg, daily, and from Apr2020 and ongoing at 20mg, daily. Historical vaccine included first dose of BNT162B2 on 17Jan2021 09:30 given intramuscularly for COVID-19 immunisation. The patient reported that recently, she received her COVID vaccine and about a month later, on 13Mar2021, she was hospitalized due to abnormal uterine bleeding. The patient has no significant medical history gynecologically, so she wanted to see if there was any correlation with receiving the vaccine and her abnormal uterine bleeding. The patient further stated that she was bleeding heavier than normal and was hospitalized because she had a heavy uncontrollable bleeding that started on 16Mar2021, and also had larger than normal clots, started on 15Mar2021, which presented like fibroids or endometriosis, however, she does not have any of these. The patient had three episodes. On 16Mar2021, the patient went to the emergency room due to bleeding. The patient was there most of the day and was sent home later on. On 17Mar2021, she went to the emergency room by ambulance and was admitted to the hospital. The patient lost so much blood that she had to have five transfusions. The patient was also treated with blood pressure medications because everything was coming out. While in the hospital, the patient had a uterine artery embolization. After discharge, she followed up with the gynecologist who followed her through the hospital. She had no gynecological history of any kind prior to this. The doctors were unable to give a definite explanation as to why this happened. It may have been hormonal at this time in the patient's cycle. She was over a year post-partum from having her last child and she had two C-sections with no issues. The patient stated that this could be completely coincidental. At the hospital on Mar2021, the patient had labs and an ultrasound. The results were in her patient portal online. She had blood work drawn a few days after hospital discharge ordered by the gynecologist and another blood work several weeks later, ordered by her primary care provider. The patient was placed on Iron 325mg by mouth twice daily and was prescribed pain medication, but the patient never took it. The patient was currently taking doxycycline 100mg tablets every 12 hours for inflammation response from the uterine artery embolization procedure that she had. The patient was unsure if this was coincidence or related. The vaccine was the only thing she can think of that may have been a contributing factor. The patient went to emergency room and was hospitalized due to the events. The patient was discharged from the hospital on 21Mar2021. Outcome of the events abnormal uterine bleeding, and bleeding was recovered on 19Mar2021, for event clot blood was recovered on 18Mar2021, and for other events was unknown.