The Covid vaccines from Pfizer, Moderna and AstraZeneca cause unexpected vaginal bleeding in older women and those using contraception, a study has confirmed.
Although changes in bleeding and periods in menstruating women after the injection have been known for years, few studies have looked at the impact on women who do not normally menstruate, such as the elderly and women using contraception.
But a new study – which looked at data from more than 20,000 women in this category – found that the risk of vaginal bleeding increased two to three times in the four weeks after the Covid vaccination compared to before the jab.
The risk was three to five times higher in postmenopausal and premenopausal women.
Researchers looked at data from August and September 2021.
Ninety-eight percent of women surveyed reported receiving their Covid vaccines in January 2021, meaning they received the original Covid vaccine, as opposed to any updated booster shots.
Experts aren’t entirely sure why changes in menstruation occur, but some believe the vaccine causes some part of the body’s tissue to become inflamed, causing changes in the uterine lining and hormone levels throughout the body.
Vaginal bleeding in postmenopausal women can be a sign of a serious condition, such as cancer, and more women in this group than the others sought medical help after experiencing unexplained bleeding – 30.6 percent
Moreover, in Norway, where the data was collected, Covid vaccines manufactured by Moderna, Pfizer-BioNTech and AstraZeneca were used, among others.
When Covid vaccines were first rolled out, tens of thousands of women complained of late or unusually heavy periods.
Before any formal investigation was conducted, anti-vaxxers seized on the reports and used them to scare Americans that the vaccines caused infertility.
However, later released research found that although menstrual changes do occur after the Covid vaccination, they are minor, temporary and do not affect fertility.
Experts aren’t entirely sure why changes in menstruation occur, but some believe the vaccine causes some part of the body’s tissue to become inflamed, causing changes in the uterine lining and hormone levels throughout the body.
Although the recent study did not investigate why these women experienced unexplained vaginal bleeding, also known as breakthrough bleeding, scientists did suggest that it could be related to the spike protein used in the injections.
Study author Kristine Blix from the Norwegian Institute of Public Health in Oslo said: ‘From the early days of the pandemic, we had already sent out biweekly questionnaires to participants to monitor the effects of the pandemic.
‘In the first COVID-19 vaccination questionnaire sent in 2021, some women reported in free text fields that they had had heavy menstrual bleeding.
‘This encouraged us to ask about bleeding patterns in a structured way.’
Researchers looked at data from nearly 22,000 women who had already experienced menopause, women in perimenopause, the time just before entering menopause, and non-menstruating premenopausal women, including some who were using long-term hormonal contraception.
They found that 252 postmenopausal women (3.3 percent), 1,008 perimenopausal women (14.1 percent) and 924 premenopausal women (13.1 percent) reported unexplained or breakthrough vaginal bleeding throughout 2021.
Of the women who reported this, about half of each group reported that their bleeding occurred within four weeks of their first and/or second vaccine dose.
The data showed that 45 percent of postmenopausal women, 51 percent of perimenopausal women and 55 percent of premenopausal women reported the unexplained bleeding.
Of these women, 28 percent of those in perimenopause characterized the bleeding as heavy, compared with 18 percent of both women who had completed menopause and who had not yet experienced menopause.
Women in the study’s senior cohort were 61 to 88 years old and were considered non-menstruating. Other non-menstruating women were between 32 and 64 years old. Respondents were then grouped into the three menopause categories.
Vaginal bleeding in postmenopausal women can be a sign of a serious condition, such as cancer, and more women in this group than the others sought medical help after experiencing unexplained bleeding – 30.6 percent compared to 13.8 percent of women in perimenopause and 9.3 percent of premenopausal women.
The risk of breakthrough bleeding in the first four weeks after a dose of the Moderna vaccine was associated with a 32 percent increase compared to the Pfizer-BioNTech vaccine.
Heavy menstrual bleeding has since been added as a side effect of the vaccine.
The study, published this week in the journal Science Advances, analyzed data from an ongoing health study called the Norwegian Mother, Father, and Child Cohort Study.