Birth Control Pills May Offer Protection Against COVID-19

New research has found that estrogen-containing birth control may help lower infection rates and reduce the severity of symptoms in those infected with COVID-19. Specifically, researchers found people who take the combined oral contraceptive pill (COCP)—which contains both estrogen and progesterone—had fewer positive cases and fewer hospitalizations.

The study, published ahead of print by King's College London, relied on data from nearly 600,000 UK women entered into the COVID Symptom Study App during May and June. Because estrogen, a sex hormone, has been shown to boost the immune system's response to viral infection, the researchers anticipated the protective effect of estrogen-containing birth control.

"For patients in whom combined oral contraceptive use is appropriate, these findings have the potential to influence decision-making when choosing a birth control method given this possible added non-contraceptive benefit," Adrienne Davis, APRN, WHNP-BC, a board-certified women's health nurse practitioner based in Georgia, tells Verywell. Davis was not involved in the King's College study. "Further evaluation of how estrogen may magnify [immune system] effects could be very promising in terms of prevention of COVID-19 and reduction in the severity of symptoms."

Estrogen and COVID-19

To get a broad look at the link between estrogen levels and COVID-19, researchers segmented data into three groups:

1. Pre-menopausal people assigned female at birth using the COCP form of birth control
2. Post-menopausal people assigned female at birth
3. Post-menopausal people assigned female at birth taking hormone replacement therapy (HRT)

Researchers then compared the 295,689 study participants taking the birth control pill to a control group of 231,436 people assigned female at birth of the same age not taking any form of birth control or hormonal therapy. While this age range of 18 to 45 included post-menopausal people assigned female at birth, 85% were pre-menopausal.

People assigned female at birth using the pill had a lower rate of predicted COVID-19, a lower hospitalization rate, and a reduced frequency of symptoms, including:

• Persistent cough
• Delirium
• Loss of smell
• Severe fatigue 
• Loss of appetite
• Pain

Post-menopausal people assigned female at birth ages 40 to 60 who were not on any form of birth control or hormone therapy had higher rates of predicted COVID-19 than others, and slightly higher rates of hospitalization. Researchers say this is because estrogen levels decline after menopause.

Interestingly, post-menopausal people assigned female at birth ages 50 to 65 taking hormone replacement therapy—which often includes estrogen—did not show the same lower predicted COVID-19 rates as younger women taking the pill. However, the COVID Symptom Study App included little information regarding HRT type, route of administration, and treatment duration, so the information may be incomplete.

More Research Is Needed

It is important to note that this study is a preprint. This means it has not been peer-reviewed and evaluated and should not be used for clinical guidance.

Not all experts are convinced estrogen is protective against the pandemic.

"I do not believe there is enough information to make the claim that estrogen exposure reduces the rate of COVID-19 or the severity of its symptoms," Dedra Sally, MSN, WHNP-BC, CNM, a board-certified women's health nurse practitioner and certified nurse midwife based in North Carolina, tells Verywell.

Above all, Sally says the younger age of the pre-menopausal people assigned female at birth taking the COCP explains their lower COVID-19 risk more than estrogen can, at least when compared to those who are post-menopausal.

"Women on combined oral contraceptives tend to be younger and in the pre-menopausal state," she says. "It's possible that post-menopausal women are more susceptible to COVID-19 due to age-related factors and comorbidities rather than having less estrogen exposure."

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