Discussion
The present study included 5709 participants, with 4464(78.2%) having
received COVISHIELD, and 1245(21.8%) had COVAXIN against COVID-19
infection. Of the total 5709 participants, 333(5.8%) developed
post-vaccination irregularities of menstruation with 32.7% having
frequent cycles (every ≤20 days), 63.7% prolonged cycles
(>38 days), and 3.6% inter-menstrual bleed. A total of 301
participants (5.3%), noticed changes in the amount of bleeding during
menstruation, with 50.2% having excessive, 48.8% scanty bleeding, and
0.99% had amenorrhea followed by heavy bleeding. Furthermore, the
irregularities of the menstrual cycle (p=0.011) and cycle length (0.001)
were significantly higher in the COVAXIN group (7.2%) as compared to
the COVISHIELD vaccine (5.3%). No significant difference was observed
in the duration and amount of menstrual bleeding in the two vaccine
groups (p>0.05). A total of 721 (12.4%) participants
complained of newly developed or worsening pre- and post-menstrual
symptoms. These symptoms were significantly higher in the COVISHIELD
group (p=0.031).
Similar results of the impact of COVID-19 vaccination on menstrual
cycles were reported by other studies from all across the world. A study
conducted on 950 women to know the impact of COVID-19 vaccination on the
menstrual cycle, reported changes in frequency (normal 43.47%,
infrequent 25%, and frequent 31.53%), regularity (regular 51.08%,
irregular 42.93%, and absent/amenorrhea 5.97%), duration (normal
65.21%, prolonged 26.08%, absent/amenorrhea 8.69%), and volume (heavy
41.84%, light 20.65%, and amenorrhea 6.52%) of menstruation in 184
women out of 408 fulfilling the inclusion criteria. It was concluded
that COVID-19 vaccination can influence the menstrual cycle and cause
alterations.19 A recent cross-sectional study from the
Middle East and North Africa was conducted on 2269 females fully
vaccinated against COVID-19 infection to assess the impact of vaccines
(AstraZeneca, Sinopharm, and Pfizer) on menstrual abnormalities and
reported that 66.3% of participants reported abnormal menstrual
symptoms post-vaccination with the resolution of these symptoms within 2
months in 93.6% of participants. Similar to our study it was observed
that vaccine type did not significantly affect the incidence of
abnormalities (p > 0.05). Furthermore, they also reported
that participants with confirmed previous COVID-19 infection had a
similar percentage of menstrual abnormalities compared to those who did
not have COVID-19 infection. Hence, it was concluded that women
subjected to COVID-19 vaccines experienced menstrual abnormalities
including, longer menstruation duration and increased menstrual cycle
lengths.20
Another cohort study was conducted in the United States of America on
3,959 women (vaccinated 2,403; unvaccinated 1,556) to assess the
association between COVID-19 vaccination (Pfizer-BioNTech, Moderna and
Johnson & Johnson/Janssen vaccines) and changes in menstrual cycle
length. It was observed that the COVID-19 vaccine was associated with a
< 1-day change in cycle length compared to pre-vaccine cycles.
Hence, it was concluded that COVID-19 vaccination was associated with
only a small change in the cycle length but not the duration of
menstrual bleeding.11 Another similar study was
conducted on 19,622 women between 18-45 years of age to know whether the
COVID-19 vaccines (Pfizer-BioNTech, Moderna, Oxford-AstraZeneca, and
Johnson & Johnson) were associated with menstrual changes. It was
reported that vaccinated women had a < 1-day adjusted increase
in the cycle length as compared to the unvaccinated ones. Furthermore,
it was observed that the adjusted difference was larger in women who
received two doses. Hence, it was concluded that COVID-19 vaccination
was associated with a small and temporary change in the menstrual cycle
length without affecting the bleeding duration.21 A
similar recent study was conducted on 9,652 women (8,486 vaccinated;
1,166 unvaccinated) to know the impact of COVID-19 vaccines on the
menstrual cycle length. All the participants were followed for 10 cycles
and it was found that the vaccinated women had a small increase in mean
cycle length. It was concluded that COVID-19 vaccination was associated
with an immediate short-term increase in menstrual cycle
length.22
Very few studies have been conducted to know the impact of COVID-19
vaccination on pre-and post-menstrual symptoms. A recent
questionnaire-based study compared menstruation characteristics
(regularity, volume, intermenstrual bleeding, and dysmenorrhea) before
and after receiving the COVID-19 vaccine in Saudi Arabia and reported a
significant impact of COVID-19 vaccination on menstrual
disturbances.23
In the present study a total of 721(12.6%) participants suffered from
COVID-19 infection before, during, or after the completion of
vaccination. Of these, 584(81.0%) participants received the COVISHIELD
vaccine and the remaining 137(19.0%) had the COVAXIN vaccine (p=0.236).
No significant difference was observed in the incidence of COVID-19
infection with either COVAXIN or COVISHIELD vaccines
(p>0.05). When comparing menstrual abnormalities including
cycle length, and amount of bleeding among those with a history of
COVID-19 infection before, during, or after vaccination, no significant
associations were observed (p >0.05). A similar study was
conducted on 483 women from Jordan and Iraq to evaluate menstrual
changes in women post-COVID-19 infection. It was reported that 47.2% of
women suffered from a change in the number of days between two
consecutive cycles, and a change in the amount of bleeding during menses
post-infection. Hence, it was concluded that COVID-19 infection may
affect the menstrual cycle pattern in females.24Similar results of menstrual cycle disturbances in women post-COVID-19
infection have been reported by other studies25-27,
but still, further research is necessary for better evidence and
conclusion.