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expert reaction to pre-print looking at estrogen levels and risk of COVID-19

A preprint, an unpublished non peer-reviewed paper posted to medRxiv, looked at estrogen levels and risk of COVID-19.


Dr Melanie Davies, Consultant Gynaecologist, University College London Hospitals & member of Medical Advisory Council, British Menopause Society, said:

“As men are more likely than women to develop severe COVID-19 infection, there is an interesting theory that oestrogen might be protecting women. But no conclusions can be drawn about estrogen use and COVID-19 severity from this report. There are some important caveats. The data are collected on an app and are self-reported, which brings bias into the study as different groups of people may not use the app equally. This is a preprint of the study findings, so it has not undergone the process of peer-review and there may need to be changes.”


Dr Richard Quinton, Consultant and Senior Lecturer in Endocrinology, Royal Victoria Infirmary, Newcastle, and Newcastle University & a member of the Society of Endocrinology, said:

“A limitation is that this is based on symptoms, rather than proven Covid-19.

“Also, the findings are not entirely coherent with each other. Their data on postmenopausal women suggests that, although they are at higher risk of risk of developing serious complications of COVID-19, taking oestrogen-based HRT is not associated with any benefit; if anything slightly the opposite. 

“Also, we know that risk of serious Covid-19 disease increases with age (although for each age-band, males have around 3-fold greater risk), so as postmenopausal women are typically older then premenopausal women, these observations might still simply reflect age-effect.

“The COCP observation is interesting, but if true, would necessarily imply a benefit from suppressing the body’s production of endogenous 17,beta,oestradiol and replacing this with the synthetic oestrogen ethinylestradiol, for which there isn’t really any mechanistic explanation.”


Dr Edward Morris, President of the Royal College of Obstetricians and Gynaecologists, said:

“This epidemiological study alone does not provide enough information about the impact of hormones on COVID-19 severity. Further research is required to fully ascertain the impact of the different types of hormone replacement therapy (HRT) and the combined oral contraceptive pill (COCP) on the severity and experienced symptoms of COVID-19 among women.”


Mr Haitham Hamoda, Consultant Gynaecologist & Chair of the British Menopause Society, said:

“This pre-print does not provide conclusive evidence that hormone replacement therapy (HRT) and the combined oral contraceptive pill (COCP) impact COVID-19 severity. As research is limited in this area we feel that for those women currently using these preparations the benefits of HRT and COCP outweigh any possible impact that they may have on COVID-19. Overall, this is an interesting concept which requires further research.” 


All our previous output on this subject can be seen at this weblink:


Declared interests

None received.

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