blood clots on her menstrual bleeding/Menstruation disruption; She has been having spotting in between periods for about 3 months/week later she starts with spotting for a day or two. / Bleeding/spotting between periods, / blood watery/thinner consistency.; After receiving 2nd dose, when she had her period, she had a heavy period.; Extra period, so 2 periods in a month cycle; This spontaneous case was reported by a consumer and describes the occurrence of MENSTRUAL DISORDER (blood clots on her menstrual bleeding/Menstruation disruption), INTERMENSTRUAL BLEEDING (She has been having spotting in between periods for about 3 months/week later she starts with spotting for a day or two. / Bleeding/spotting between periods, / blood watery/thinner consistency.), HEAVY MENSTRUAL BLEEDING (After receiving 2nd dose, when she had her period, she had a heavy period.) and POLYMENORRHOEA (Extra period, so 2 periods in a month cycle) in a 34-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 023C21A and 023C21A) for COVID-19 vaccination.     The patient's past medical history included Flu from 29-May-2021 to 02-Jun-2021 and Fever from 29-May-2021 to 02-Jun-2021.   On 16-Jun-2021 at 12:30 PM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) .5 milliliter. On 17-Jul-2021 at 1:30 AM, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .5 milliliter. On 15-Aug-2021 at 11:30 AM, the patient experienced MENSTRUAL DISORDER (blood clots on her menstrual bleeding/Menstruation disruption), INTERMENSTRUAL BLEEDING (She has been having spotting in between periods for about 3 months/week later she starts with spotting for a day or two. / Bleeding/spotting between periods, / blood watery/thinner consistency.), HEAVY MENSTRUAL BLEEDING (After receiving 2nd dose, when she had her period, she had a heavy period.) and POLYMENORRHOEA (Extra period, so 2 periods in a month cycle). At the time of the report, MENSTRUAL DISORDER (blood clots on her menstrual bleeding/Menstruation disruption) and INTERMENSTRUAL BLEEDING (She has been having spotting in between periods for about 3 months/week later she starts with spotting for a day or two. / Bleeding/spotting between periods, / blood watery/thinner consistency.) had not resolved, HEAVY MENSTRUAL BLEEDING (After receiving 2nd dose, when she had her period, she had a heavy period.) was resolving and POLYMENORRHOEA (Extra period, so 2 periods in a month cycle) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, SARS-CoV-2 test: negative (Negative) Covid ruled out, tested twice.         Concomitant medication provided includes supplements. No treatment medications were reported. It was reported that patient had a heavy period after the second dose of vaccine. A week after periods spotting was occurred for a day or two. She had normal cycle before. She had 2 periods in month after the vaccine administration but there after it went back to normal as one period a month. Heavy bleeding and clots was gradually subsided but spotting between periods was not recovered.  It was reported that she never had these issues before and she didn't changed anything in her lifestyle. She was very aware of any changes in her periods and she had been kept her track of her cycle for years and kept records On 30 Jul 2021 patient had periods and on 15 Aug 2021, the patient had an extra period, so she had 2 periods in a month cycle. On 06 Sep 2021, 09 Sep 2021, 10 Sep 2021, 07 Oct 2021, 24 Oct 2021, 25 Oct 2021, 26 Oct 2021, 27 Oct 2021 and 28 Oct 2021 the patient had spotting. Case seriousness is downgraded (thrombosis that was the only serious event is recoded and assessed as non-serious) due to lack of evidence of seriousness from a regulatory or clinical standpoint according to source document (reported as non-serious).   Most recent FOLLOW-UP information incorporated above includes: On 01-Nov-2021: Follow up document received contains: new events added, patient demographic details, medical history, reporter details, event outcome and events onset date  was updated. On 02-Nov-2021: Follow up contains no new information.