Michelle Obama, the former US first lady, has revealed that she used IVF treatment to conceive her two daughters Malia and Sasha after once suffering a miscarriage.
In a deeply personal interview, Mrs Obama, who is married to former US president Barack Obama, also made public that the pair had undergone marriage counselling.
The revelations were made both in her new memoir, Becoming, which will be published on Tuesday, and a promotional interview for the book she gave to ABC News.
They provide an intimate portrayal of a relationship that sat at the heart of the White House for eight years during Mr Obama’s presidency, which ended in January 2017.
Miscarriage followed by IVF
During the ABC News interview Mrs Obama discussed the struggles she had conceiving in her early marriage and how suffering a miscarriage left her feeling “lost and alone”.
"I felt like I failed because I didn't know how common miscarriages were because we don't talk about them. We sit in our own pain, thinking that somehow we're broken,” Mrs Obama said.
The pair eventually turned to IVF treatment which led to the conception of her two daughters, Malia and Sasha, who are now aged 20 and 17.
“The biological clock is real because egg production is limited,” Mrs Obama said. “I realised as I was 34 and 35, we had to do IVF.
"I think it’s the worst thing that we do to each other as women, not share the truth about our bodies and how they work.”
How marriage counselling helped
Asked why she chose to reveal the pair had marriage counselling, Mrs Obama said: “For those young people out there who think that marriage is supposed to be easy.
“Marriage counselling for us was one of those ways where we learned how to talk out our differences. What I learned about myself was that my happiness was up to me.
“And I started working out more, I started asking for help, not just from him but from other people. I stopped feeling guilty.”
The memoir fulfills half of an agreement that publisher Penguin Random House reached with her and Mr Obama for each to publish a book, reportedly for a sum worth more than $60 million. She will go on a 10-city tour to promote the book, including a stop in London.
Fury over Trump's 'birther' claims
Mrs Obama also criticises Mr Trump for fuelling the so-called ‘birther movement’, which demanded Mr Obama produce his birth certificate to prove he was born in America. Only US citizens are allowed to be president.
Mrs Obama wrote in the book that she would “never forgive” the current president for “putting my family’s safety at risk”.
“The whole [birther] thing was crazy and mean-spirited, of course, its underlying bigotry and xenophobia hardly concealed. But it was also dangerous, deliberately meant to stir up the wingnuts and kooks,” she wrote.
Asked about that comment on Friday, Mr Trump hit back by saying Mrs Obama "got paid a lot of money to write a book and they always insist that you come up with controversy."
He added: “Well, I’ll give you a little controversy back. I’ll never forgive him for what he did to the United States military by not funding it properly.”
'Buzzed with fury' over Trump tape
She expresses disbelief over how so many women would choose a "misogynist" over Hillary Clinton in 2016. She remembers how her body "buzzed with fury" after seeing the infamous "Access Hollywood" tape, in which Mr Trump brags about sexually assaulting women.
Mrs Obama also accuses Mr Trump of using body language to "stalk" Mrs Clinton during an election debate. She writes of Mr Trump following Mrs Clinton around the stage, standing nearby and "trying to diminish her presence."
Mr Obama launches her promotional tour on Tuesday not at a bookstore, but at Chicago's United Center, where tens of thousands of people have purchased tickets - paying anything from just under $30 to thousands of dollars - to attend the event moderated by Oprah Winfrey.