text: (CNN)Erika Langhart had a zest for life. By the time she finished college she had already visited 37 countries. After graduating from college she was working in Washington and thinking about going to law school. Her life was full of promise, but all that ended suddenly when she was just 24 years old. In Phoenix, Karen Langhart was looking forward to her daughter coming home for Thanksgiving when she received a call from Erika's cell phone. In an interview with CNN, Erika's mom said she "picked up the phone and answered it, 'Hi Schmoo, can't wait to see you' -- Schmoo-bear is our nickname for her -- and it was Sean." With groceries in hand, Erika's boyfriend, Sean Coakley, had arrived at her apartment to make dinner and found Erika collapsed on the floor. The fire department and paramedics were already on the scene. The attendant at the front desk had heard Erika screaming for help and called 911. "[The paramedics] tried to revive her with CPR and while they were in the apartment, I think she had a heart attack and then two more on the way to the hospital in the ambulance, and another one in the hospital, and she never woke up," Erika's father, Rick Langhart, said. Karen knew it was serious when the emergency room doctor said they needed to come to the hospital in Arlington, Virginia.  She said the doctor asked her whether Erika was using any birth control. According to Karen, when she told him Erika was using the NuvaRing, . "He said well there's a link between NuvaRing and pulmonary embolisms," Karen Langhart said. Rick Langhart said doctors removed the NuvaRing immediately. "It was, it was a nightmare," he added. By the time Rick and Karen arrived at the Virginia Hospital Center, Erika was in a coma, in the ICU. "They had determined that Erika had no brain activity and that because of her heart attacks they basically told us that she was brain dead and that's it," Rick Langhart said, fighting back tears. Hospital records cited the NuvaRing as a risk factor for Erika's multiple pulmonary embolisms. Records confirm what Erika's parents told CNN: that a blood clot started in an artery/vein in her right thigh and traveled to her lungs, causing "massive" pulmonary embolisms and "multiple episodes of cardiac arrest" on the way to the hospital and overnight. The Langharts never heard their daughter's voice again.  She died on Thanksgiving. "We miss her so much," Karen Langhart said. Less than a year later, 2,000 miles away in Utah, Megan Henry had the scare of her life. Henry, it turns out, was a classmate of Erika Langhart's at American University. She's training to compete in the Olympics in skeleton, a type of high-speed downhill sledding.  The scare that shook her in August 2012 threatened her Olympic dreams. Within weeks of starting the NuvaRing, Henry said she collapsed during training, unable to breathe. "I mean I was struggling, I was struggling to breathe." Henry said. "It's like an elephant was sitting on my chest all the time." After seeing five doctors who were unable to tell her what was wrong, she finally got a diagnosis from a pulmonologist. He told her he thought she had blood clots in her lungs. "I said, you know I started taking this birth control, is it related to this?" Henry said. "And he was like, yeah, I definitely think that you have blood clots and it's from the birth control." X-rays, followed by an ultrasound and a CAT scan, revealed that Megan's life was in danger. "[The doctor] started to tell me, you have multiple pulmonary embolisms in both lungs," said Megan. "They're sending an ambulance, they're going to come and they're going to rush you to the emergency room ... it just really took me by surprise and you know I knew it was something bad but I never imagined it would be something like that." According to her hospital discharge papers, the NuvaRing Henry was using "was probably the risk factor" for her pulmonary embolisms. Henry went from peak physical condition to using a breathing machine. She was put on blood thinners, too.  Her doctors told her it's too risky to use hormonal birth control again. "Easy. Safe. That's really how it was presented -- easy, safe, low-dose hormone -- you know, and it turns out it wasn't. It wasn't that at all," she said. Even though NuvaRing has about the same risk for blood clots as newer birth control pills, Henry said she wishes she had known that the incidence of life-threatening blood clots is double with NuvaRing compared to older birth control pills. "There are other options out there for birth control that have risks, but not doubling the risks," Henry told CNN. "If I would have known that I never would have taken it." And thinking about what happened to her classmate, Erika, Henry said, "I think if I knew what I know now and, you know, if Erika had known that, a number of people, I think that they would have made a slightly different choice." The NuvaRing is one of the most popular birth control products on the market. A flexible ring inserted vaginally, it releases a combination of hormones. By 2010 as many as 830,000 women were using the vaginal ring as a contraceptive method, according to the Guttmacher Institute, a nonprofit organization advancing sexual and reproductive health worldwide. At least 10.5 million women use hormonal birth control pills. The NuvaRing was approved by the FDA in 2001 and became available to women in the United States in 2002.  The Dutch pharmaceutical company, Organon, developed the device and manufactured it until 2007 when the company was sold to Schering Plough Corporation, which was then acquired by Merck in 2009. According to Merck, the NuvaRing is sold in more than 50 countries, and 44 million prescriptions have been filled for women in the United States alone. The NuvaRing dispenses what's called a third-generation progestin, or synthetic hormone. When it first came on the market, the device was touted as a breakthrough -- inserted vaginally to release a "continuous low dose of hormones."  It stays in for three weeks, so no bother of taking a daily birth control pill.  The ring was branded in a television commercial as "a different way to do birth control" and "Oh! It's easy to use." Convenient? Absolutely. But safe? That depends on whom you ask. The Langharts had no idea the NuvaRing birth control their daughter had been using for four years had already been linked to other women's deaths, according to unconfirmed claims of problems reported to the FDA. Merck acknowledges a very small risk of blood clots but stands by its product, saying, "There is substantial evidence to support the safety and efficacy of NuvaRing." While studies have shown that the number of severe adverse events is extremely low -- fewer than 11 cases per 10,000 women who use it for a year -- the families who have lost loved ones point out that the incidence of life-threatening blood clots is double with NuvaRing than with older birth control pills. Since the mid-1990s there have been multiple studies suggesting that while third-generation progestins are generally safe, they are approximately twice as likely to cause blood clots than older, second-generation birth control pills. Merck denied CNN's request for an on-camera interview. Instead, it gave this statement: "While there is a very small risk of a blood clot when using NuvaRing or any combined hormonal contraceptive, this risk is much less than the risk of blood clots during pregnancy and the immediate post-partum period." Among 10,000 women, between five and 20 women run the risk of developing a serious blood clot during pregnancy; the risk increases to between 40 and 65 women during the 12-week postpartum period. Among 10,000 women in a year using combination hormonal contraceptives -- that includes birth control pills, the ring and the patch -- the risk of developing serious blood clots ranges between three and 12 women. NuvaRing users are on the higher end of that risk. Two studies conducted in 2011 and 2012 reveal the risk of developing a serious blood clot among NuvaRing users is 11.4 and 8.3 per 10,000 women in a year, respectively.  The NuvaRing's label was updated in 2013 by the FDA with information about both studies. The Langharts, Megan Henry, and 3,800 others sued Merck. According to claims filed in federal and state courts, the lawsuits allege Organon, the original manufacturer of the NuvaRing, "failed to adequately warn consumers about a heightened risk of blood clots associated with the use of NuvaRing, even though the manufacturer was aware that NuvaRing posed greater risks than other hormonal contraceptives." In February, without admitting any wrongdoing, Merck agreed to pay $100 million in damages. But the Langharts did not settle, insisting Merck be held accountable for what the family said was Merck's failure to properly warn users of the risk.  They believe what Merck is getting away with is "criminal." "I don't understand why a company in the United States would allow that kind of product on the market. It's not the way Americans do business," Rick Langhart said.  "And for them to do what they do in total disregard for what's going on. It's criminal to me." Instead, to honor Erika's memory, they decided to create a nonprofit to inform women of the dangers they believe are related to the NuvaRing and the comparative risks of all forms of hormonal contraceptives. The nonprofit's name, "Informed Choice for Amerika," honors their daughter's name.
target: The NuvaRing is one of the most popular birth control products on the market .
  Lawsuit cites "a heightened risk of blood clots associated with the use of NuvaRing"
  Maker: "There is substantial evidence to support the safety and efficacy of NuvaRing"