Indian scientists decode post-Covid vax menstrual irregularities in women

The Covid pandemic continues to haunt humanity for the last two years with the infection graphs going up and down after intervals across the globe. The vaccine against the infection has augmented the fight against the SARS-CoV-2 virus and has saved lives and helped in taking human life back on track.

However, a short menace accompanied the event of mass vaccination efforts and that is the menstrual disturbance in females being reported.

In a recently published article in the world’s first most cited open access journal in the field of immunology, ‘Frontiers in Immunology’, the Indian researchers have reported the menstrual troubles included delay or early menstruation, heavier bleeding pattern, painful sessions and breakthrough bleeding.

The paper — “Understanding the trauma of menstrual irregularity after Covid vaccination: a bird’s-eye view of female immunology” — has compiled data from the reports of three countries showing significant figures on this subject. A US cohort of 2,403 females showed that 55 per cent of females receiving the Pfizer vaccine, 35 per cent relating to Moderna and 7 per cent linking to Johnson and Johnson/Janssen vaccine underwent changes in their cycle length. The Norwegian young adult cohort also informed heavier bleeding, increase in duration of menstruation and even shortening of interval between two cycles. In the UK cohort of 39,591 females, menstrual disturbances were also testified.

The paper has been authored by researchers and doctors from the department of microbiology, Swami Shraddhanand college, University of Delhi; Munshi Singh College, BR Ambedkar Bihar University; department of biochemistry, Jan Nayak Chaudhary Devilal dental college, Sirsa and department of radiation oncology, All India Institute of Medical Sciences, Patna, India.

Females during their reproductive age owing to their menstrual cycle show different immune response to various factors they are exposed to. For a 28-day menstrual cycle, the first 14 days are called follicular phase which starts with the bleeding days of the first 5-6 days. During these 14 days, females have higher antibodies in their body that nature has bestowed them to fight against potential infections. However, this also makes them prone to auto-immune disorders during this phase. The 14-16th day are ovulatory days, which is followed by rest 14- 12 days of luteal phase.

During this phase, the immune system is suppressed and inflammation is low. At the time of menstruation (bleeding), females are more likely to experience debilitating symptoms of asthma or arthritis. All of this clearly points towards one important observation that the immune response in females is variable during her menstrual cycle, said the lead author of the article Dr Rinki Minakshi while talking to IANS.

“The vaccine may act as a stressor for the body, which could have an impact on the pattern of menstruation. The time of vaccination with respect to the phases of the menstrual cycle could be a deciding factor when it comes to foreseeing the effect of vaccination in females,” Dr Rinki Minakshi told IANS.

“We have discussed previous incidences of menstrual disturbances post-vaccination that involved vaccines against typhoid, Human Papilloma Virus and Hepatitis B. So this is not for the first time, scientists have reported this issue. During the initial days of vaccine roll-out programme, myths were getting circulated that Covid-19 vaccine causes infertility. Our article emphasises that the future studies in this field would stem such rumours about the vaccine,” said Dr. Rinki Minakshi.

One of the co-authors Dr. Abhishek Shankar from AIIMS Patna said that although the matter of menstrual disturbance isn’t universal, the fraction of female cohorts showing the issue is significant. He added that clinical trials must include criteria of the female’s age as a major factor deciding the efficacy of drugs or vaccines.

Dr. Archana Ayaggari, who also co-authored this article said that the marginalisation of females in clinical trials would ignore the well-being of females. “Any sort of menstrual disturbance becomes a cause of anxiety in females because their daily routine goes haywire,” she said, adding that openness on this front would promote more and more female candidates to take vaccine shots without any element of scepticism.

(Avinash Prabhakar can be reached at


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