Idina Menzel knew the odds were not in her favor.
During her in-vitro fertilization journey in 2018, the Frozen star was warned by doctors that getting pregnant wasn't a guarantee.
"I was doing it at such a late age and the doctors were saying, ‘You might be one of those rare women that it works for at this age,'" Idina, 51, shared in an exclusive clip from the Dec. 25 episode of Sunday TODAY with Willie Geist. "The competitive person in me was like, ‘I'm going to do it.'"
But while undergoing fertility treatments during her 2018 national tour, Idina ultimately learned that another child wasn't in the cards for her and husband Aaron Lohr.
However, the Wicked alum—who shares son Walker, 13, with her ex-husband Taye Diggs—still wanted to give fans an honest look at her fertility reality in the new documentary Idina Menzel: Which Way to the Stage?
"I didn't want to make people squeamish about it because my legs were in stirrups," she joked to anchor Willie Geist. "I wasn't sure, but it was happening at that time."
In her documentary, streaming now on Disney+, cameras rolled as Idina gave viewers an intimate look at her IVF experience, including doctor appointments and the toll it took on her body.
"As couples know, who are experiencing and going through IVF, you have to catch these cycles with your body and some months are good and your body is giving you good count with your follicles and your eggs," she said on TODAY. "Some months aren't or if it didn't work and you're pumping yourself with these hormones, sometimes you have to let your body recalibrate."
For Idina, she hopes the project reminds women that they are not alone.
"No matter what the outcome, I just wanted women to feel seen in this film and people to understand what we go through," she told People Dec. 6. "It was important to me to forgo the privacy of that and allow people to have a little window into that experience."
To hear more from Idina, watch Sunday TODAY With Willie Geist, Sunday mornings at 8 a.m. EST on NBC.
(E! and NBC are part of the NBCUniversal family)