COVID-19 infection linked to abnormal uterine bleeding

COVID-19 infection linked to abnormal uterine bleeding | Image Credit: © brizmaker - © brizmaker - stock.adobe.com.

There is an association between COVID-19 infection and abnormal uterine bleeding (AUB), according to a recent study published in Clinical Science.¹

Recent concerns have arisen about menstrual disturbances during the COVID-19 pandemic, potentially caused by disease infection, vaccination, or pandemic-related stress. However, data linking each factor independently to menstrual cycles remains limited.

Menstruation is often perceived as a sign of fertility and health in women, causing menstrual disturbances to often lead to anxiety and stress.² Ovarian sex hormones have also been linked to modulation of disease susceptibility and severity.¹ This highlights a need for increased understanding about the impact of COVID-19 infection on menstruation.

Investigators conducted a review to assess the impact of COVID-19 on uterine bleeding. Typical menstrual bleeding was identified based on the International Federation of Gynecology and Obstetrics Abnormal Uterine Bleeding System 1 as a frequency of 24 to 28 days, duration of no more than 8 days, and subjectively normal flow volume.

AUB is reported in 1 in 4 women, defined as frequent or infrequent, prolonged, irregular, or heavy menstrual bleeding (HMB). HMB is defined as excessive menstrual blood loss adversely impacting a woman’s quality of life. Figures for HMB are consistently high, with excessive menstrual loss reported by 1 in 3 women.

Causes of AUB are categorized as structural or non-structural. Structural cases can be identified through routine examination, unlike non-structural cases. However, non-structural cases may be identified through a detailed clinical history and examination, with data supported by laboratory tests if needed.

While multiple studies found an association between COVID-19 infection and abnormal menstrual cycle patterns, the most validated association was reported in the online survey titled “The COVID-19 Pandemic and Women’s Reproductive Health.” A relative risk (RR) of 1.38 was reported for heavier vs normal flow in infected patients vs non-infected patients.

Infected patients also more commonly experienced frequent vs normal cycles and more vs no changes in mid-cycle spotting, with RRs of 1.3 and 1.31, respectively. These associations remained following adjustments for pre-existing gynecological conditions and exogenous hormone use.

With this data supported by other studies, investigators determined a likely association between COVID-19 infection and abnormal menstrual cycles. This highlights the need for mechanisms to inform clinical services about patients experiencing menstrual disturbances after COVID-19 infection.

A surge of research has occurred evaluating the impact of COVID-19 vaccination on menstrual disturbances. This includes the Nurse’s Health Study, which found a higher risk of increased cycle length in vaccinated women vs unvaccinated women, with an adjusted odds ratio of 1.48. However, this association was only found in the first 6 months.

In the Apple women’s health study, participants receiving an mRNA vaccine or the J&J viral vector vaccine had a slight increase in menstrual cycle length of 0.5 days for the first dose and 0.39 days for the second dose. These changes reverted by the subsequent cycle.

Other studies reported similar associations between COVID-19 vaccination and menstrual disturbances. These disturbances remained limited to the vaccination cycle or resolved by 6 to 9 months, indicating no long-term impact. This data may be useful for clinicians providing information about the likelihood of symptoms to their patients.

Long COVID is defined as sustained post COVID-19 infection sequalae, with symptoms lasting for at least 2 months. Data has indicated long COVID in twice as many women as men, highlighting the need to determine long COVID’s impact on reproductive health.

A patient led survey reported menstrual disturbances in 33.8% of women with long COVID, including irregular periods in 26% and heavy periods in 19.7%. This indicates long COVID in women is associated with increased risks of menstrual disturbances.

Overall, this data highlights associations between mechanisms of COVID-19 and AUB. Investigators concluded data about this association can be used to inform policy and understand post-viral syndromes.

References

1. Maybin JA, Watters M, Rowley B, Walker CA, Sharp GC, Alvergne A. COVID-19 and abnormal uterine bleeding: potential associations and mechanisms. Clin Sci (Lond). 2024;138(4):153-171. doi:10.1042/CS20220280
2. Karlsson TS, Marions LB, Edlund MG. Heavy menstrual bleeding significantly affects quality of life. Acta Obstet Gynecol Scand. 2014;93:52–57. doi.org:10.1111/aogs.12292