After 13 hours of intensifying pain, two trips to the emergency room and two CT scans, doctors finally found what was ailing Lottie Green.
In her left lung, the pulmonologist told her, was the largest blood clot they had ever seen and there were others in her right lung as well, she said.
Soon after the 41-year-old Bethesda, Md., resident was released from a hospital last month, Ms. Green joined hundreds of other women in lawsuits against Germany's Bayer AG, the maker of the popular oral contraceptive Yaz.
Her attorneys say thousands more lawsuits are forthcoming after the British Medical Journal in August published a study that found higher risks of clots, heart attacks and strokes with Yaz and its predecessor, Yasmin, compared with other contraceptives.
Bayer and the U.S. Food and Drug Administration cite other studies - Bayer funded two of them - that reported no increased cardiovascular risk for the company's products compared with others. All oral contraceptives' users are at higher risk of cardiovascular side effects than the general population - as the products' labels warn.
A spokeswoman said the FDA is funding another study, which won't be ready for a year.
Bayer has drawn enough scrutiny from the FDA that plaintiffs' attorneys have been on the case for more than a year, said Tim O'Brien, a partner in the law firm Levin Papantonio in Pensacola, Fla.
"They had poor dosage control at their manufacturing plant and they aggressively marketed Yaz to the teenage and immediate post-teenage crowd" for unapproved uses, said Mr. O'Brien, who has 260 clients for lawsuits against Bayer.
Among them are 21 Washington-area clients such as Ms. Green who are also represented by Andrew Bederman, a partner in the law firm Greenberg & Bederman of Silver Spring, Md.
"Virtually every client is young and healthy," Mr. Bederman said. "They seem to have no previous relevant medical problems."
The FDA reprimanded Bayer late last year for overstating the benefits and downplaying the risks of Yaz in television advertisements. The slogan for Yaz was "beyond birth control."
Bayer marketed Yaz to women in their 20s. Commercials cultivated a hip, youthful image set to rock music, and advertised Yaz as a treatment for acne and premenstrual syndrome (PMS).
But the FDA said "the TV ads are misleading because they broaden the drug's indication, overstate the efficacy of YAZ, and minimize serious risks associated with the use of the drug," in the warning letter to Bayer HealthCare Pharmaceuticals, a Montclair, N.J., unit of Bayer.
Yaz has not been approved as a treatment for PMS and the drug should be used to treat acne only by those who want to use an oral contraceptive, the agency said.
Yaz is approved - only among women who want to take oral contraceptives - for premenstrual dysphoric disorder, a severe form of PMS that afflicts up to 10 percent of menstruating women, according to the Mayo Clinic Web site. PMS is much more widespread, affecting nearly eight times more women, according to the clinic.
The FDA ordered Bayer to run a $20 million "corrective" ad campaign.
"I can't think of anything even remotely as large scale as this corrective advertising," said Michael A. Santoro, an associate professor of business ethics at Rutgers University.
In August, the FDA warned Bayer about quality control at a German plant that makes one of Yaz's key ingredients - drospirenone, a relatively new progestin, or synthetic hormone - which the British study blamed for the contraceptive's increased cardiovascular risk.
Combined contraceptives such as Yasmin and Yaz, unlike older birth control pills, use both estrogen and a progestin to prevent ovulation.
Bayer spokeswoman Rose Talarico said the company takes the quality control issue "very seriously" and is working on it with the FDA.
The company also insists that Yaz and Yasmin are safe and effective, and Ms. Talarico said it will "defend itself vigorously" against the lawsuits.
"The complaints we have reviewed so far pertain to side effects that are warned about in the labeling of all contraceptives, including ours," Ms. Talarico said.
The FDA agrees.
"The safety profiles for Yasmin and other combined hormonal contraceptive products containing estrogen ... are similar," spokeswoman Karen Riley said.
For Ms. Green, the reality that she had almost died took awhile to accept.
The former screenwriter and aspiring novelist writes romantic comedy, not medical tragedy.
Her apartment is furnished with Hollywood props, from the swoosh-shaped bookcase to the "Brady Bunch"-era entertainment center.
"I felt like I had been hit by the cattle catcher [on a locomotive]," she said. "I didn't understand the severity of what was happening to me," Ms. Green said. "It was a couple of days later, I said, 'Wow, I almost died.' "
Six days in the hospital on two blood thinners dissolved the clots and saved her life. She will have few lingering effects, though two weeks after her release she said she is "incredibly tired most of the time."
Now, Ms. Green is focused on spreading the word about what has happened to her and so many other women, which she blames on Yaz.
"It's not just women who are my age; it's younger women. There's no reason for blood clots to be forming except for this pill and it's a very scary situation," she said.
Back in October, before her hospitalization or any symptoms, she saw a television commercial by Mr. Bederman's firm about Yaz.
She asked her gynecologist about it, and "she told me I was fine on it," Ms. Green said.
"I will not be going back to her," she said.