There are many false myths on social media about vaginas, and one woman has made it her mission to correct them. Dr Jen Gunter has been a practising obstetrician-gynaecologist in the US and Canada for 25 years. She is a fierce advocate for women's health and has been described as Twitter's resident gynaecologist.

Recently she took up arms against claims that putting jade eggs into vaginas supported "hormonal balance, menstrual regulation, and bladder control". Gunter showed that they were not part of any ancient Chinese tradition nor did they have any scientific backing. The claims were taken down.

Gunter's latest book, The Vagina Bible, is a best-seller in several countries. It's full of practical advice, designed to empower women and help them to look after their health. Here are some facts she feels everyone with a vagina should know.

Image copyright Emma Russell

1 - It's important to know your vagina from your vulva

The vagina is inside the body - it's the muscular canal which connects the uterus to the outside world. What you can see from the outside, the part that touches your clothes, is the vulva.

Gunter says it's crucial to know the correct terminology, and not to use euphemisms.

"When you can't say the word vagina or vulva, there is an implication that there's something dirty or shameful about that," says Gunter.

She points out that the medical term "pudenda" which describes the outside of the vulva, comes from the Latin "pudet", which means "it shames".

Gunter thinks using such labels is not only harmful to women on an emotional level, but can have an impact on them medically as well, because patients may not be able to describe exactly what's going on and get the right treatment.

2 - The vagina cleans itself

Gunter has noticed a real shift in women's attitudes over the last 10 years, with many believing they need to use products to modify the smell of their vagina. In North America, up to 57% of women have cleaned vaginally in the past year, with many reporting that they are encouraged to do so by their sexual partner.

But Gunter says there is no need to use anything to clean inside the vagina.

"It is a self-cleaning oven," she says.

She especially warns against using scented douches.

"It's a vagina, not a pina colada," she says. "Douches are like cigarettes for your vagina."

Even water can disrupt the delicate ecosystem, increasing the risk of contracting sexually transmitted infections. Steaming, another trend, is not only unnecessary, but can lead to burns.

The outside, the vulval area, can be cleaned when necessary, with water or a gentle cleanser.

Soap can strip the acid mantle, which acts like a protective waterproofing for the skin. If hormonal changes during the menopause make things dry and uncomfortable then it's fine to use something like coconut or olive oil.

Vaginal cells are replaced every 96 hours - a much faster turnover than other parts of the skin - so it can heal quickly.

Image copyright Emma Russell

3 - Your vagina is like a garden

The vagina contains an army of "good" bacteria which help to keep it healthy.

"The vaginal microbiome is like a garden of all different kinds of bacteria that function together to keep the vaginal ecosystem healthy," says Gunter.

The good bacteria produce substances that create a slightly acidic environment, which stops any "bad" bacteria taking hold, as well as mucus which keeps everything lubricated.

This is why wiping inside with an antibacterial wipe is not good - it's important to keep the balance of bacteria. Similarly, Gunter advises against using a hairdryer to dry the vulva: the skin is meant to be moist there.

Image copyright Emma Russell

4 - Pubic hair is there for a reason

Gunter has noticed a growing trend for women to remove all of their pubic hair. This is helping to make pubic lice homeless, but there are also risks to genital depilation.

"When you wax or shave or sugar, you are causing microscopic trauma to the skin," says Gunter. "We see cuts, abrasions, infections from pubic hair removal as well."

She advises making sure the hair removal practitioner doesn't double-dip the wooden sticks into the wax, which could spread bacteria between clients.

If shaving, use a clean razor, prep the skin appropriately and go in the direction of hair growth, to avoid increasing the risk of ingrown hairs, which can get infected.

Above all, Gunter wants people to make an informed choice.

"Pubic hair has a function, it is probably a mechanical barrier and protection for the skin," she says.

"It may also have a role in sexual functioning because each pubic hair is attached to a nerve ending - that's why it hurts to remove it."

5 - Getting older can affect the vagina

After years of having periods and maybe children, the ovaries stop producing eggs and menstruation stops. The amount of hormones in the body which keep women fertile drops dramatically - and low levels of oestrogen, in particular, affect the vagina and vulva.

These tissues, which were once kept moist with mucus, can atrophy, and the resulting dryness can cause pain during sex because of a lack of lubrication.

This might sound depressing, but Gunter says most women can get help with this from their doctor. And some manage well with over-the-counter lubricants.

"I think it's really important for women to know about that," she says. "You don't have to suffer."

There is a myth (borne out of poor research) that having sex will help to keep things in working order but the micro trauma to the vaginal tissues can leave them vulnerable to infection.

Dr Jen Gunter spoke to Health Check on the BBC World Service

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