Sophie, Countess of Wessex has become the first royal to speak publicly and at length about going through the menopause.
The 56-year-old says that she has experienced brain fog during official engagements that has caused her to lose her train of thought.
The countess also called for franker conversations about menopause, periods and the pressure on women to “look 25 years old” even in middle age as she became patron of the Wellbeing of Women charity.
“You know in the middle of a presentation when you suddenly can't remember what you were talking about, try being on an engagement when that happens – your words just go,” she said on a video call with Sarah Jane Cale, founder of the Positive Menopause website.
"And you're standing there and going, 'Hang on, I thought I was a reasonably intelligent person, what has just happened to me?'
"It's like somebody's just gone and taken your brain out for however long before they pop it back in again and you try and pick up the pieces and carry on."
Sophie has also discussed hot flushes and memory loss, both symptoms of the menopause, with typically occurs in people between the ages of 45 and 55.
While speaking to Ms Cale, she suggested that people should “have the knowledge” not to question women who say they’re hot, even when it’s cold outside.
She added that young girls should be taught about the menopause, saying: "How much are young girls actually told at the beginning? Because I don't remember having these lessons at all.”
The countess also discussed the “superficial” pressures women face to appear youthful, even as they reach middle age.
"We've got to be fit, we've got to be clever, we've got to be looking skinny, we've got to be looking beautiful, we've got look 25 years old for the rest of our lives," she said.
"But unfortunately our bodies are going, 'Well, you now, that's fine, you can do all of that on the outside as much as you possibly can, or as much as you can possibly afford to'.
"But on the inside things are a little different, you know. The inside hasn't been listening to social media, it's just gonna happen."
While speaking to Wellbeing of Women chief Dame Lesley Regan, Sophie called for a end to the taboo around the menopause.
"We all talk about having babies, but nobody talks about periods, nobody talks about the menopause, why not?" she said.
"It's not only about dialogue with women and young girls, it's men as well – this is a conversation that has to be opened up to everybody. Even if they don't want to listen - we just have to get louder."
Wellbeing of Women, a London-based charity founded in the 1960s, invest in research into health issues including pregnancy, birth complications, gynaecological cancers and wellbeing issues such as menopause and endometriosis.
