Pregnant or taking the pill? Here’s what to know about COVID-19, blood clots and hormones – ABC News

For the most part, being a woman gives you an upper hand if you get diagnosed with coronavirus.

Research shows women are less likely to become severely ill or die from the disease.

It's unclear exactly why our biological sex might make us more or less resilient, but females tend to have more robust immune responses, and sex hormones are thought to play a role.

There is, however, one way in which hormones specifically oestrogen may increase the risk of COVID-19 complications.

According to new guidelines from the Royal Australian College of General Practitioners (RACGP), women who have been severely ill with COVID-19 should stop using combined hormonal contraception.

That's because COVID-19 can increase the risk of blood clotting a risk that's already heightened with the use of hormonal contraceptives that contain oestrogen (which make blood clots more likely).

So what does the risk of clotting mean for other women taking oestrogen-containing medicine, or for those who are pregnant?

First up, it's important to note that the new guidance only applies to people on birth control who have been severely ill with COVID-19 those who had an acute infection and/or developed severe post-COVID-19 illness.

"This is a cautionary piece of advice to be aware that people might be at an increased risk of blood clots if they've had these severe infections," said Amy Moten, chair of the RACGP's special interest group on sexual health medicine.

"We're now seeing potential long-term consequences ... and one of them appears to be that people with more serious episodes of COVID-19 have an increased risk of blood clotting."

So far, there is no evidence to suggest COVID-19-related blood clotting is occurring more frequently in women on birth control, or among women who are pregnant or using hormone therapy (both of which increase levels of oestrogen).

Under normal circumstances, the absolute risk of getting a blood clot while taking the pill is extremely low.

"Around two to four people out of 10,000 over one year might develop a blood clot. For people on the pill, the risk might be around double that," Dr Moten said.

The risk can depend on the type of pill and the dose of oestrogen and progesterone.

There are also other known risks for blood clots and their complications.

"Whether you have a strong family history of someone having a blood clot, people with a high BMI, people who smoke, particularly over the age of 35, all have independent risk factors for blood clotting," Dr Moten said.

For women who have had an asymptomatic or mild case of coronavirus and use combined hormonal contraception, there is no reason to stop using or switch contraceptives.

If GPs do advise people to stop taking a combined hormonal contraceptive, Dr Moten said they should transition the patient onto something like a progesterone-only contraception or a barrier method.

Progesterone-only contraceptives include intrauterine devices (IUDs, sometimes known by the brand name 'Mirena'), the contraceptive implant (sometimes known by the brand name 'Implanon'), the contraceptive injection, and the progesterone-only pill (sometimes known as the 'mini pill').

"These are all very established to be safe in people who have risk factors for blood clots, and so the advice for COVID-19 doesn't apply to this progesterone-only contraception," she said.

Hormone replacement therapy or HRT is a medication containing the hormones that a woman's body stops producing after menopause. It's used to treat menopausal symptoms.

Dr Moten said although there were some situations in which HRT may be inadvisable, a COVID-19 diagnosis wasn't one of them.

"It is a lower risk overall because of the dose and types of oestrogen involved in those particular medications," she said.

"There are some kinds of oestrogen-only menopause hormone therapies that don't have any increased risk of [blood clotting]."

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Pregnancy causes major fluctuations in hormone production, and, in general, pregnant women are at an increased risk of blood clotting.

According to Australia's National COVID-19 Clinical Evidence Taskforce, hospitalised pregnant women with an acute infection, such as COVID-19, are at an even greater risk.

But endocrinologist and professor of women's health Susan Davis said the jury was still out on the risks of COVID-19 in pregnancy.

"Although women who are pregnant are not highly protected against getting infected, they appear to be relatively protected from severe COVID-19," said Professor Davis of Monash University.

"There's not a lot of data the number of studies that have looked fully at pregnant women is small.

"But it appears that either there is no increase in adverse effects in pregnant women, or [that] pregnancy may be protective."

While increased levels of oestrogen in the body (from medication) can increase the risk of blood clotting, naturally occurring oestrogen can also have a protective effect.

"The pill is different [it] contains a synthetic oestrogen, which is far more potent than the one our body makes," Professor Davis said.

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Naturally occurring oestrogen may actually help women to mount an immune response to COVID-19.

"COVID-19 gains entry into cells through a receptor called ACE-2," Professor Davis said.

"It can be activated in ways that heighten inflammation or in ways that suppress inflammation.

"By chance, oestrogen also activates ACE-2 but triggers the path that's anti-inflammatory."

In many cases, people who become severely unwell or die from COVID-19 do so because of an overactive, hyper-inflammatory response to the virus.

"Oestrogen and progesterone dampen down the inflammatory immune response," Professor Davis said.

While biological sex differences may impact a person's vulnerability to COVID-19, the better survival rates among women over the age of 80 when hormone levels in both sexes equalise suggest sex hormones are not the only factor contributing to different mortality rates.

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Pregnant or taking the pill? Here's what to know about COVID-19, blood clots and hormones - ABC News