Dr Heather Rupe, an obstetrician-gynecologist from Tennessee, US, sought to reassure women never to be embarrassed of their bits.
Writing for WebMD, Dr Rupe said: “As someone who sees about 35 vaginas a day, I can assure you that they come in all shapes and sizes.
“Life, childbirth, weight gain, sexual activity, gravity, and hormonal changes can have an effect on the contours of the vagina over time, but is this a problem?
“Can a vagina be too big? If a woman hasn’t had an exceptionally difficult vaginal birth or any type of vaginal surgery, then no.”
Dr Rupe said the vagina – the canal between the womb and the opening – is about four inches long, and three inches wide.
Dr Suzy Elneil, consultant at University College Hospital, London, wrote for the NHS website: “Like people, vaginas are completely individual. No two are the same.
“Vaginas vary in shape, size and colour. Some are small and ovoid [egg-shaped], some are large and cylindrical, and the colours can vary from light pink to a deep brownish red-pink. The important thing is that the vagina functions normally.”
As for the labia – the lips on the outside, part of the vulva – these also come in all shapes and sizes and shouldn’t be compared.
The vagina gets bigger during sex and for childbirth.
It’s a bit like a rubber band, being able to stretch and then spring back to its normal shape.
Even after stretching out for childbirth “most revert back to normal quite quickly”, said Dr Rupe.
Therefore, it is a myth that a vagina can be “loose” – regardless of how much sex a woman has, it is not possible.
There are muscles around the vagina – as well as the bladder and bottom – that need to be kept in check.
These are pelvic floor muscles, and can weaken with age or childbirth.
Keeping the pelvic floor muscles strong will not only ensure you could hold urine, but make sex better, the NHS says.
It can increase sensitivity during sex and give “stronger orgasms”. For men, it can help treat erectile dysfunction.
You can feel your pelvic floor muscles if you try to stop the flow of urine when you go to the toilet.
Pregnant women are advised to start pelvic floor exercises immediately – if they aren’t already doing them.
This will protect the muscles from becoming lax during childbirth, potentially leading to incontinence.
Dr Rupe urged against getting any products that claim to tighten the vagina because they are simply ineffective.
She said: “Do not use any type of over-the-counter vaginal ‘tightening sticks’ or ‘herbal remedies’ to try to tighten or shrink your vagina.
“These work by causing irritation to the vagina that induces swelling. I have seen patients with severe vaginal burns from these products requiring hospitalisation.”