Changes to menstrual cycle following the date of vaccination and continuing for 4 cycles so far.   For context, I have been extremely regular and on schedule since I first started getting my period at age 11. I am now 28. I get my period once monthly, with a period coming typically every 27-30 days after the start of the previous period cycle. Occasionally the gap will be 26 days with most being 32 days, which is rare. I normally bleed for 7 days, but occasionally only for 6 and at most 9, which includes very light extended spotting. The first day of my period is some spotting, then second and third days consist of the bulk of bleeding with one of these days being considerably heavier than the other. The fourth and fifth consist of red blood but not heavy and the last 2-3 days consist of brown spotting. I experience breast tenderness within the week prior to starting my period and occasionally get pelvic cramps. I use an app on my phone to track the dates and flow of my period so I will be providing specific dates below.   The only previous exception to my regularity was in April 2020 at the beginning of the pandemic, which I will detail below later to contrast the changes I have been experiencing since getting vaccinated.  I would like to highlight that I have never experienced ovulation spotting between periods as some women do when an egg implants. I have also never been pregnant and am not currently trying to conceive if that info is needed. As indicated by the rest of the form, I do not have any health conditions that would effect my menstrual cycle and am not currently taking medications that might effect it either.   I got the Moderna vaccine, receiving the first dose on 4/27/21 and the second dose on 5/27/21. My first menstrual cycle after getting the second dose was initially normal, starting and ending between 6/13/21-6/20/21, but followed only 14 days from the start of the previous period on 6/27/21 by another period which lasted for 9 days between 6/27/21 and 7/5/21. My flow was normal except my end of period spotting lasted about 4 days. These back to back periods mark the first time I have ever had periods occur so close together.   I went to my gynecologist during the 6/27/21-7/5/21 cycle and had blood work done to determine the cause. My hormone levels were normal, as was my thyroid function, so she gave my a 10 day dose of Provera to try and regulate my cycle again. I started the prescription I believe on 7/3/21 and finished it on 7/12/21. I experienced light spotting from 7/9/21-7/10/21. According to the information that came with the prescription, I should have started a new period 3-7 days after finishing the pills. This did not occur and my next period came on 7/28/21. It lasted 4 days and consisted of only brown spotting between 7/28/21-7/31/21, marking 32 days between cycle start dates which as mentioned above is quite rare. From 8/15/21-8/20/21, which was a 6 day period coming only 19 days between cycle start dates, I experienced only brown spotting.   My latest period came on 9/4/21, 21 days after the start of the last period. My flow returned to the normal flow pattern mentioned above between 9/4/21 and 9/9/21, but was followed by an extended time of spotting from 9/12/21 to 9/14/21 after a two day gap. Since the start of my menstrual changes, this past period has been more normal than the last few but still not fully back to normal.   My other physical symptoms of breast tenderness and cramps have been irregular as well. I would sometimes get them and sometimes would not throughout these past 4 months   My early pandemic abnormality in April 2020 consisted of extended spotting between periods. I had a normal period from 3/22/20 to 3/27/20, then on 4/7/20 I experienced 8 days of light spotting. On 4/15/20, about when I was due for my next actual period, I started what would be my usual period flow pattern and continued it to the period?s conclusion on 4/22/20. After this, my periods returned to their normal cycle pattern and continued to be normal until I was vaccinated for COVID-19. I strongly believe THIS abnormality occurring in April 2020 was due to either heightened stress from the uncertainties and dangers of the pandemic or the possibility that I had COVID but was otherwise asymptomatic and did not think to correlate this change with having the virus. I had no reason at the time to get tested so I have no way of knowing if the latter might be the case.   Stress otherwise I believe would be the culprit. I was terrified to leave the house, very worried about my frontline worker friends and family, and the reported case and death tolls keep skyrocketing more and more each day. When I had to make a quick trip to my work office after we started working from home I was extremely anxious the entire ride there and back and especially so during the few minutes I was inside even though only one other person was present in the building. I was also not taking any medications at the time and no other changes to my life aside from the pandemic. As time went on, I like most people got used to the social distancing, mask regulations, and necessary caution in public and it?s long since became second nature.   I bring this all up because I was NOT stressed out about getting vaccinated. I was glad I could get it when it became available to the general public and most people had be reported to respond well to the vaccine. I actually felt relieved that I would be safer in public now that I was vaccinated. So stress has no place in what I?m currently experiencing. The only major changes to my life have been the vaccine.