Anita Rachvelishvili was pregnant when she began to lose her voice.It was the middle of 2021. She and her husband had tried for years to conceive, and it seemed like a child would be the storybook ending to being forced to slow down during the pandemic. Rachvelishvili, the Georgian mezzo-soprano, had spent the previous decade crisscrossing the world, blazing through some of the most difficult parts in opera.She made her name with a potent combination of capacious sound and interpretive subtlety. In 2018, Riccardo Muti, the pre-eminent Verdi conductor, called her “without doubt the best Verdi mezzo-soprano today on the planet.” Peter Gelb, the Metropolitan Opera’s general manager, recently said: “She was the greatest dramatic mezzo-soprano singing. It seemed there was no big, meaty role she couldn’t tackle.”Rachvelishvili sang Carmen, the role of her 2009 breakthrough, hundreds of times, and was scheduled to ring in 2024 as Bizet’s classic antiheroine in the splashy premiere of a new production at the Met.Instead, the show will go on without her. Rachvelishvili, 39, will spend New Year’s Eve at home in Tbilisi, where she was born, as she tries to reconstruct the fundamentals of the voice that brought her stardom and then abandoned her.“It is a nightmare, a total nightmare,” she said over dinner in September at a rustic restaurant nestled in the woods outside the city. “I’ve had two years of nightmare at this point.”Transforming the body and causing sweeping hormonal changes, pregnancy is rarely easy for opera singers, who rely on a carefully calibrated physical apparatus to dependably produce huge waves of unamplified sound. Rachvelishvili had not quite felt herself in the handful of performances she did while she was carrying the baby — her voice, she said, came out “scratchy and strange” — but she assumed things would return to normal after the birth.Lioness: Rachvelishvili at the Tbilisi State Conservatory, where she studied after auditioning with a Whitney Houston song.Daro Sulakauri for The New York TimesShe delivered her daughter, Lileana, in late November 2021, and something still felt different, though the lower part of her voice was, if anything, bigger than before. She figured she could handle the low-lying role of Marfa in Mussorgsky’s “Khovanshchina,” which she was to rehearse in Paris just a month later — months sooner than many singers return after giving birth.“It was the worst decision of my life,” she said, sitting alongside Otari Maisuradze, her husband — who became her vocal coach, too, after a rift with her teacher early in her crisis.Over a week of conversations, meals, walks and drives in and around Tbilisi, Rachvelishvili described how rushing back to the stage had helped set off an agonizing dance of one step forward, two steps back. Seeming improvement would be countered by dispiriting nights, and the increased size of her low notes was offset by the sudden disappearance of her high ones. Her once-steady confidence and smooth column of sound were both fractured.“You start having big panic attacks, then you lose control completely,” she said. “Of breath, of body. Everything.”Her husband spoke softly. “She was my lioness,” he said. “I am very proud I have very strong women in my family. But these two years, with this trouble, she became like a little cat.”A VOICE IS A MYSTERIOUS, largely invisible amalgam of body and psyche — of tiny, vibrating vocal cords; muscles that provide support for the breath; cavities through which sound resonates; and the self-belief to fearlessly deploy it all. Problems are inevitable, though the path to overcoming them is uncertain, since medical interventions can be chancy. And talking about them is still stigmatized within the industry, perhaps in part because responses to artists are already so subjective that illness or injury can cloud later evaluation even if the difficulty has been “fixed.”“Every singer, at some point, will have some kind of vocal issue,” said the soprano Sondra Radvanovsky, who made an arduous recovery from surgery on her cords earlier in her career. “It’s like football players: Every quarterback has some shoulder issue at some point.”Rachvelishvili warming up with her husband, who has become her vocal coach.Daro Sulakauri for The New York TimesMaria Callas couldn’t undo her instrument’s unraveling. In an essay about her, the conductor and critic Will Crutchfield once wrote, “There is no example of an important operatic singer encountering serious vocal problems and returning to form.”That is true, to a point. The tenor Jonas Kaufmann has been open about vocal issues, yet has managed to keep singing challenging parts at a high level. But Rolando Villazón, another 21st-century star tenor, never recovered from his troubles.“Every singer goes through that fear of the high notes, or feeling not really comfortable with your voice,” Rachvelishvili said. “I just need to have this battle with myself, by myself. Nobody else can help me. I need to remember how I was, and how Anita did it.”THOUGH SHE CAME TO OPERA LATE — she sang a Whitney Houston song when she auditioned for conservatory — Rachvelishvili was not merely an intuitive natural talent but also a smart, dedicated musician. She slowly built on a firm technique and stuck to her relatively low signature role as she waited and worked.“I sang Carmen for so many years because I didn’t have easy high notes,” she said. “I took time to learn how to do those notes so that the body knew what it was doing.”Those notes grew stronger without her pushing, and she practiced diligently to incorporate the nuances, colors and seductive soft singing that set her apart from many who shared her repertoire. She sang the wild Azucena in Verdi’s “Il Trovatore” with startling refinement in 2018 at the Met, where her triumphs culminated in a scorching run as the Princesse de Bouillon in Cilea’s “Adriana Lecouvreur” early in 2019.Rachvelishvili and Otari Maisuradze with their daughter, Lileana, who was born in November 2021. Rachvelishvili’s vocal problems began when she was pregnant.Daro Sulakauri for The New York TimesHer future seemed limitless. In addition to Azucena and Verdi’s Eboli and Amneris, major roles in “Les Troyens,” “Werther,” “La Favorite” and “La Gioconda” were on the horizon. With her powerful high notes, sumptuous tone and onstage intensity, it seemed that Wagner’s Ortrud, Fricka, Kundry and even Isolde — the province of big-voiced sopranos — might be possible.Then came the pandemic. Rachvelishvili had struggled to get pregnant in the past, but she said that the drastic reduction in travel and stress in 2020, as well as the hormones prescribed by her doctor, helped it happen.Fearful of losing the baby, she was cautious in the early days of the pregnancy, but she sang some performances in mid-2021. Muti said of their concert “Aida” in Italy that summer, “She was able in the past to hold long phrases without any problem, and now going in the high register she had some difficulty.”Still, he added, “you could feel, here and there, the great singer.”When she sang “Khovanshchina” in Paris so soon after giving birth, it was possible, because of the role’s low center of vocal gravity, to believe she was back in her old shape — even if a short excerpt posted by the opera company suggests that her tone had grown more fragile, her vibrato wider, even beyond her high notes.“It was like a completely different body,” Rachvelishvili said, “with a completely different voice.”“It was like a completely different body,” Rachvelishvili said of performing after giving birth, “with a completely different voice.”Daro Sulakauri for The New York TimesIn the past, her muscular support had originated down by her pelvis, but that was disrupted by the pregnancy and birth. While she searched for a new approach, her next engagement, “Adriana Lecouvreur” at the Teatro alla Scala in Milan in early 2022, was disastrous. The Princesse’s high notes, once easy for her, refused to come. At the premiere, Rachvelishvili fled the theater in despair before her curtain call, something she had never done.“It was the most horrible experience of my life, not being able to sing the way I wanted,” she said. “I couldn’t go out after a performance like that. It’s not the old Anita they’re used to, or I’m used to. I’m not going out; it’s insulting to them, to La Scala.”She canceled the rest of the run, then moved on to Munich, where she had a long rehearsal period before she was supposed to sing her first Didon in Berlioz’s “Les Troyens.” A doctor saw inflammation on her vocal cords; it could have been allergies, acid reflux, a hormonal imbalance or laryngitis, or some combination of those factors.Unable to produce high notes or offer the elegant control of volume and texture for which she was admired, she left before the premiere. She began to lose faith in herself, which set off a vicious cycle with her physical problems.“I said to my therapist that I’d kill myself if it wasn’t for the baby,” she recalled. “I have a baby to take care of.”She was also her family’s breadwinner. Maisuradze had long ago devoted himself to supporting her career, and even star singers are freelancers.“The responsibility is huge, because everybody depends on me working,” she said. “I have my parents to take care of, and my family, and the baby. People said that if I couldn’t sing, I should just stop. And I said, ‘Will you feed my family if I stop?’ I have to at least try and try and try. I need to bring some money to the table.”But in summer 2022, she had to drop “Cavalleria Rusticana” in London and “Aida” in Salzburg before they opened. Leaving the “Aida,” Rachvelishvili released a statement citing back pain after the birth of her daughter and asking “all haters and even some colleagues” to “please stop inventing stories about me losing my voice or nonsense like this.”She retreated to Tbilisi to work. And early in fall 2022, she was able to creditably sing the generally low Dalila in Saint-Saëns’s “Samson et Dalila” in Naples, though her high notes were still problematic.“I said to my therapist that I’d kill myself if it wasn’t for the baby,” Rachvelishvili recalled. “I have a baby to take care of.”Daro Sulakauri for The New York TimesThe tenor Brian Jagde, her co-star in that “Samson” and several other productions during this period, sometimes went so far as to anchor her during scenes with a hand at her waist, to lend the lower muscular support that she no longer felt internally.“There’s nothing harder to watch than a person onstage with you that you believe in so much, and she’s struggling,” he said. “There were clear signs the top wasn’t working like she wanted it to, and she was working desperately to make it work. Sometimes it did, sometimes it didn’t.”She canceled a fall run of Verdi’s “Don Carlo” at the Met, but arrived there to sing “Aida” in December. Rachvelishvili thought the first performance went passably, but the company’s administration disagreed.“It was obvious that she was not the same singer — at least temporarily not the same singer — who had conquered our stage so brilliantly up to that point,” Gelb said, and he decided to remove her from the coming “Carmen” and a solo recital that was to have taken place earlier this month.“I had a painful discussion with her in my office, because I wanted her to hear it from me,” he said. “I said that we needed to wait until she was back singing well again, and then we’d be happy to have her return. She had a hard time accepting that.”EARLY THIS YEAR, RACHVELISHVILI was able to get through another “Samson,” in Berlin, and a new role, Charlotte in Massenet’s “Werther,” in Athens, with her body feeling more dependable. But when she returned to Munich in the spring for “Aida,” she began having terrifying panic attacks onstage, paralyzed by fear of the high notes, and left after four of eight performances.“She’s such a tough character, but she’s human,” Jagde said. “That was what I saw progress for her in a negative way: less belief in herself because of what was happening. The physical affected the mental for her.”“On 50 seconds, we are working two or three days,” Maisuradze said of Rachvelishvili’s practice routine. “They must be beautiful, the voice and colors, and stylistically true.”Daro Sulakauri for The New York TimesDropping out of all her engagements after early June, she had minor surgeries for stomach problems and to lessen the effects of acid reflux, and another procedure to remove what she said was a small polyp on her vocal cords. Since then, she has been at home in Tbilisi with her husband and daughter. Lileana, she said, is “worth everything. She’s even worth never singing again.”But she still hopes she can have both. Rachvelishvili and Maisuradze have been painstakingly reviewing her instrument and technique, going through scores phrase by phrase and restitching together her different registers, returning to the basics.“On 50 seconds, we are working two or three days,” Maisuradze said. “They must be beautiful, the voice and colors, and stylistically true.”Of her high register, Rachvelishvili said this month: “It’s not as perfect as I want, or as I had it a few years ago, honestly. But it’s much easier; it’s there; it’s not difficult anymore to take them.”The clock is ticking: A new role, Laura in Ponchielli’s “La Gioconda,” is scheduled for April in Naples, before a revival of “Aida” in Munich. Noting her voice’s solid technical foundation, Muti was optimistic.“She is young,” he said, “so she will come back. We are waiting with great enthusiasm.”Rachvelishvili has fought her panic with therapy, antidepressants and meditation, but it still lurks. “All the physical problems, the vocal problems, are gone,” she said. “Right now, I’m just battling with myself and my head to make sure that when I go onstage soon, I will feel calm inside. The joy of being back is so big that it overtakes me sometimes.”She described a recent video call with her manager. “I was doing a high note in Dalila’s second aria,” she said, “and he stopped me: ‘I see the fear in your eyes. Don’t be afraid, just go for it. You can do it without fear in you.’ And I did it, and it was perfect.” More