Candace Jones suffered monthly menstrual pains throughout adolescence, but she didn't fully understand how bad they were until she went into labor with her first child.
"The cramping was so severe you could compare it to the contractions with the baby," said the 26-year-old Springfield, Va., mother.
Since having two children and turning to a new form of birth control -- the IUD -- the cramps have subsided, she said, but the memories of missing running and swimming practices and staying in bed with a heating pad are still vivid.
Jones, like about 15 percent of all menstruating women, suffered from dysmenorrhea -- stabbing or aching lower abdominal or back pain that can cripple women for days each month.
For generations, the only treatment for menstrual pain was over-the-counter medicines like Motrin and Midol. But now, there may be a cure for the root cause of the cramping.
Scientists have created a pill that targets the cause of stomach cramps, rather than just treating its symptoms. The drug, known as VA111913, has been manufactured by the British company Vantia Therapeutics and is in clinical trials in Britain and in the United States.
So far, it has been proven safe and has few side effects and could be on the market in four years if secondary trials are successful.
'I think it would be fair to call it a breakthrough. There is certainly no other treatment like it," Vantia researcher Dr. Jim Phillips told Britain's Daily Mail. "From our research there is nothing to suggest it won't work."
During the next two months in the United States, the National Institutes of Health (NIH) will test the drug on 128 women between ages 18 and 35 who describe their menstrual pain as severe enough to interfere with daily life. They will receive VA111913 for a maximum of six days during their menstrual cycle.
Menstrual Cramp Drug for Women Without Other Problems
The drug would be used to treat primary dysmenorrhea, which is defined as pain that occurs in otherwise healthy women.
Causes of secondary dysmenorrhea can be fibroids, endometriosis, ovarian cysts, pelvic inflammatory disease and infections from sexually transmitted diseases, according to Medline Plus, an online resource for the NIH.
The new drug works as a receptor on the hormone vasopressin, which has effects on fluid balance and smooth muscles like the heart and the uterus, according to Dr. Michelle Warren, medical director of the Center for Menopause, Hormonal Disorders and Women's Health at Columbia University.
"About 15 percent of all women have cramps bad enough to keep them at home on strong pain medicine, especially in their early years under 20," Warren told ABCNews.com.
"If it last a day or more, it's considered severe," she said.
The "old standbys" like anti-inflammatory drugs are somewhat effective, according to Warren. "But getting cramps is annoying and worrisome on the day you are getting married or your senior prom."
"The pain is real," she said. "That's why they call it the curse."
Sometimes women resort to stronger painkillers that can zone them out and have numerous side effects.
Tina, a 29-year-old administrative assistant from New York City who did not want her last name used, said she suffers so severely from cramping that her mother sends her codeine-based pain medication from Britain, where it can be purchased over the counter.
Old Painkillers Can Cause Damage
On a recent doctor's visit, Tina was asked if she was an alcoholic, because of the damage the painkillers were doing to her liver. She was told to stop.
But Tina said that because the pain can be "intolerable," she continues to use the medicine.
"It's so bad that I am left to the point where I have to leave work early, crying and breaking out into a sweat," said Tina, who has been getting monthly pain since her first period at 10.
"I can't stand up and it lasts until the second or third day," she said. "I have tried other pills, but they don't work."
Painful menstruation is the leading cause of lost time from school and work among women in their teens and 20s, according to NIH data.
"A lot of this is age related," said Ellen W. Freeman, director of the premenstrual syndrome program at the University of Pennsylvania. "About 60 percent of all adolescents are troubled with menstrual cramps. But it tends to decrease with age. By the late 30s it's down to 20 percent."
For Meghan Berry, a 28-year-old Web editor from New York City, the stabbing pain was so severe she had to go on birth control pills, which she described as a "cure-all."
"They were really intense my junior and senior years in high school," she told ABCNews.com. "At their worst, I had problems standing up and doubled over. I would drive to school, but then my period would come and my mother would have to pick me up."
The new drug could be "an alternative route" for young girls who don't want to take birth control, Berry said.
"I think it's incredibly difficult for a whole host of issues when a girl has to address that with her parents," she said. "Having a complete separate drug would be really nice for these young women."
It's not only young women who might be helped by a new drug.
Mary Beth Matterfis is 43 and said she has been buckled by menstrual cramps since she was 17 or 18.
"My mother never had any cramps and the story used to be, you're like your mother," said Matterfis, who works at an investment bank. "Great. She saved it all up for me."
"Sometimes I go to stand up and my legs give out," she told ABCNews.com. "It's inconsistent for me. There are times I don't even know I have [my period] and times when I literally go into shakes and feel my heart going and have to stop because I feel faint with palpitations and cold sweats."
One day, she said, she felt her period coming on and went to get some fresh air.
"On the way back it hit me and I stood behind a store vomiting, feeling like I was going to pass out," Matterfis said.
But as bad as the pain is, Matterfis said, she is nervous about taking any kind of drug, especially ones that are stronger than ibuprofen.
"You don't want to take strong drugs when you are 17, and when you are older and in college or working you can't take them because you have to function," she said.
As for the still unnamed VA111913, Matterfis said if trials are successful, she will ask her doctor about its safety and side effects.
"If they can prevent some of these things from happening to me every month -- how long will I get this in all, for 12 periods a year and 40 years or more? -- that would be a miracle," she said.