There is no evidence that vaccines cause spontaneous bleeding in women

Many cases of strong vaginal bleeding and irregularities in the cycle have been reported after vaccination, but it has not been yet possible to establish a cause-effect relation


A web self-defined as Catholic has echoed the results from a report published by an organisation known as America’s Frontline Doctors (AFLDS) in which they ensure having “knowledge of hundreds of reports related with vaginal bleeding, postmenopausal vaginal bleeding and spontaneous abortions” after vaccination against covid-19”. This is MISLEADING: many cases of strong vaginal bleeding and irregularities in the cycle have been reported after having received the vaccination, but it has not been yet possible to establish a cause-effect relation.

"AFLDS has knowledge of thousands of reports related to vaginal bleeding, postmenopausal vaginal bleeding and spontaneous abortions after vaccination against COVID-19"

Despite it was not gathered as a secondary effect in the leaflets, some health professionals raise the possibility that there is actually a relationship between the vaginal bleedings and the covid-19 vaccine, as it is observed in this commentary in an article at the British Medical Journal requesting more information. On its part, VAERS, the US notification service of side effects, has gathered “a total of 9000 reported cases”, as Adelaida Sarukhan, an immunologist and science writer at the Institute for Global Health (ISGlobal, in Catalan) in Barcelona, indicates to Verificat. These events include strong bleedings, irregularities in the cycle or, even, bleeding in menopausal women.

VAERS does not assure causal association

It is important to highlight that the reported cases by VAERS do not involve causal association and, for the moment, there is no scientific evidence supporting a cause-effect relation. For this reason, professionals insist in that, for the moment, “there is very few, not to say null, scientific evidence relating vaccination for covid-19 with the change of menstrual bleeding pattern”, as Josep Perelló, assistant doctor at the Gynaecology and Obstetrics Service of the Hospital de Sant Pau (Barcelona) and vice-president of the Catalan Society of Contraception, points out.

In fact, according to the expert, “there is no scientific evidence that a vaccine conditions an alteration of menstrual bleeding”. He cites the case of papillomavirus “for which alterations in the bleeding pattern have been reported” and, however, “no association could be established”. 

Hormonal changes during the menstrual cycle

It is worth remembering that during the menstrual cycle a series of hormonal changes take place ending with menstruation: “There are a lot of factors that can influence in this hormone system and cause an alteration of the menstrual cycle, what can drive to an absence of menstruation, both abundant or scanty menstrual bleeding, and intermenstrual bleeding, among others. One of the most well-known factors is stress”, details the expert.

He has also seen cases of women who have reported alterations in bleeding patterns, a fact that was already repeated “during the beginning of the pandemic, without having been able to establish a clear association to date”. In his opinion, these cases could have been more linked to an attention bias: “Bleeding pattern alterations are very frequent and therefore they are frequently reported. Most women are not usually as aware of their bleeding pattern as we may think. When you are doing a new or investigational treatment, in this case the covid vaccine, more attention is paid to possible adverse effects”.

On her part, Sarukhan considers that “it has also not been thoroughly investigated, and certainly the clinical trials did not look at this type of event in a specific manner”. Both experts coincide at signaling that these are in any case “temporal” irregularities and that are no reason to not get vaccinated. “It is true that no relation between the alteration bleeding pattern and covid vaccination has been established but, in case it was established, this would be punctual, reversible, and without any type of consequence for woman’s health”, Perelló concludes.