In the book, due to be published on Tuesday, she also reflects on early struggles in her marriage to Barack Obama as he began his political career and was often away.
Obama, 54, said she and her husband and former president Barack Obama underwent fertilization treatments to conceive daughters Sasha and Malia, now 17 and 20.
She writes that they met with a counselor "a handful of times", and she came to realize that she was more "in charge" of her happiness than she had realised. "We had to do IVF".
Obama's memoir "Becoming" releases on November 13.
Former first lady Michelle Obama discusses her dislike of President Donald Trump - as well as personal details of her life before and during her time in the White House - in her highly anticipated memoir, "Becoming", The Washington Post reported Thursday. "And for this I'd never forgive him". "Donald Trump, with his loud and reckless innuendos, was putting my family's safety at risk", she wrote. And I want them to know that Michelle and Barack Obama, who have a phenomenal marriage and who love each other, we work on our marriage. "My moment of self-arrest".
The president also blasted a reporter who asked whether his newly-appointed Attorney Genera Matthew Whitaker would get involved in special counsel Robert Mueller's probe into alleged Russian interference in the 2016 presidential election. "But it was also risky, deliberately meant to stir up the wingnuts and kooks", Michelle wrote.
She writes that her body "buzzed with fury" after seeing the infamous Access Hollywood tape, in which Trump brags about sexually assaulting women.
"The whole [birther] thing was insane and mean-spirited, of course, its underlying bigotry and xenophobia hardly concealed", Obama wrote in her memoir, according to a Washington Post review. She writes about Mr Trump following Mrs Clinton around the stage, standing nearby and "trying to diminish her presence".
And when Trump was elected president, she says she was surprised that so many women would choose a "misogynist" over "an exceptionally qualified female candidate".
Mrs. Obama called the conspiracy "crazy and mean-spirited", and said it endangered her family.
And while Trump suggested Obama left him with "old and tired" military equipment, Harvard University professor Matthew Bunn noted that it was Obama who, in 2015 "laid out a $1 trillion plan to modernize every aspect of the USA nuclear arsenal over the next 30 years".