“We were trying to get pregnant and it wasn’t going well,” Mrs Obama, 54, writes in her upcoming memoir.
“We had one pregnancy test come back positive, which caused us both to forget every worry and swoon with joy, but a couple of weeks later I had a miscarriage, which left me physically uncomfortable and cratered any optimism we felt.”
In the memoir, called Becoming, she writes of being alone to administer herself shots to help hasten the process.
Her “sweet, attentive husband” was at the state legislature, “leaving me largely on my own to manipulate my reproductive system into peak efficiency”.
The revelations are some of many included in the book from a former first lady who has offered few extensive comments on her White House years.
“I felt like I failed because I didn’t know how common miscarriages were because we don’t talk about them,” the former first lady said in an interview broadcast on ABC’s Good Morning America.
“We sit in our own pain, thinking that somehow we’re broken.”
She said she and Mr Obama underwent fertilisation treatments to conceive daughters Sasha and Malia, now aged 17 and 20.
Mrs Obama also writes openly about everything from growing up in Chicago to confronting racism in public life and becoming the country’s first black first lady.