Winfrey opens up in “An Oprah Winfrey Special: The Menopause Revolution.”

Oprah Winfrey is opening up about her personal journey with menopause, revealing she had to give up her beloved pastime of reading due to menopause symptoms.

Winfrey said she experienced a loss of concentration that became so severe she had to temporarily stop leading her eponymous book club, Oprah’s Book Club.

“The worst part for me, this is when I knew I was really in trouble, is when I couldn’t concentrate reading,” Winfrey told ABC News’ Kayna Whitworth in an interview that aired Monday on “Good Morning America.” “I love reading so much, but I let go of the book club because I could not concentrate when I was reading. I could no longer finish a book.”

Winfrey continued, “I brought [the book club] back when I started taking estrogen, because I could concentrate again, but I actually never shared that before, that the real reason I had to stop it is because I could no longer concentrate. It makes me want to cry.”

Winfrey, 71, said that in addition to a loss of concentration, she also suffered from heart palpitations — a sensation of a racing or irregular heartbeat — which she said she did not know were a symptom of menopause, the time in life when a woman’s periods stop permanently.

“I didn’t have night sweats, and I didn’t have hot flashes, but I had never heard that heart palpitations [were] a symptom of menopause,” she said, adding later, “When I was going through it, there was nothing. There was nobody. I felt literally like I was going to die every single night.”

Winfrey said her own experience going through menopause is what motivated her to host a new special, “An Oprah Winfrey Special: The Menopause Revolution,” which shines a spotlight on the common life change.

The special, airing March 21 at 10 p.m. EST/PST on ABC and the next day on Disney+ and Hulu, features Winfrey’s story, as well as others who have been public about their own experiences with menopause including Maria Shriver, Naomi Watts and Halle Berry.

Though menopause is a natural process that impacts millions of women each year, the topic has for years been considered taboo to talk about publicly and has been chronically underfunded when it comes to research.

Menopause is the point in a woman’s life when she has not had any menstruation, including no bleeding or spotting, for 12 months, according to the U.S. Office on Women’s Health.

It occurs when the ovaries produce very low levels estrogen and progesterone until it eventually stops, which causes a woman’s menstrual cycles to end permanently.

The average age for menopause is 52, with only about 1% of women in the U.S. experiencing premature menopause, or menopause that happens before the age of 40, according to the Office on Women’s Health.

Symptoms of menopause may include hot flashes, mood changes, depression and anxiety, difficulties sleeping, urinary incontinence, irregular periods or bleeding, vaginal dryness and infections, and changes in libido, according to the Office on Women’s Health.

Winfrey says in the special that she experienced symptoms of menopause for around two years before realizing what was happening to her body.

She said after going through menopause herself, she wants to encourage other women to seek medical care when they first experience symptoms, instead of waiting.

“Because it affects every cell in your body, the first time you have any of the symptoms, that’s when you need to go find a doctor who will listen to you, hear you and take action for you,” Winfrey said.