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THURSDAY, July 17, 2003 (HealthDayNews) -- There's good news for women who were early users of birth control pills in the 1970s and 1980s as well as for women now taking newer versions of oral contraceptives.
A large, decades-long study confirms that nonsmoking women on the pill do not have higher overall death rates. Although mortality rates from cervical cancer were higher, these were balanced out by decreased death rates from ovarian and other uterine cancers.
Smokers have a much more grim prognosis, however. The study, appearing in the July 19 issue of The Lancet, found that overall death rates were more than twice as high for women who took the pill and who smoked at least 15 cigarettes a day as compared to nonsmokers.
Two other large studies had already published similar results. "This is a pretty solid finding with these big studies in agreement," says Dr. Martin Vessey, lead author of the latest study. "The sound statistical conclusion is that there is no harmful effect to taking oral contraceptives. That's a very important result." Vessey, an emeritus professor of public health at the University of Oxford in Britain, has been involved in the study since it began 35 years ago.
The study started by recruiting 17,032 British women between 1968 and 1974. At the time, the women were aged 25 to 39 and were white and married. All used oral contraceptives, a contraceptive diaphragm, or an intrauterine device (IUD). Many of the women ended up being on the pill for at least eight years, Vessey says.
"In common with a number of studies, we did find an increase in deaths from cancer of the cervix in pill users," Vessey says. "That was compensated for by fewer deaths from cancers of the other parts of the uterus and from cancers of the ovary. If you put those three reproductive cancers together, the net effects of the pill on the three is beneficial."
"Their findings are consistent with previous studies, and that is a slight increase in cervical cancer and a decrease in particular in ovarian cancer. We've pretty much known this for many years now," adds Dr. Sanjay Agarwal, director of the Center for Reproductive Medicine at Cedars-Sinai Medical Center in Los Angeles.
Heavy smokers, however, had more than double the death risk, largely from heart disease and stroke.
"The key to this study is the breakdown effect of smoking. It really does underline the significant detrimental effects of smoking even in young ages," Agarwal. "This study just highlights very strongly that smoking really does increase the risk of heart attacks and hemorrhagic stroke in women taking birth control pills."
So what does it mean to today's pill users? "This study mainly concerns the pills used in the '70s and '80s, and in Britain those pills were mostly pills containing 50 micrograms of estrogen. They were sort of medium dose," Vessey says. "Nowadays the pills used have lower doses of estrogen and hormones generally."
For middle-age and early elderly women who were on the pill during this time period, the results should be very reassuring -- as long as they're not smokers.
"I think you could definitely regard these findings as also being reassuring in terms of modern pills, although obviously there is a bit of extrapolation there," Vessey says.
"We would assume that lower doses equate with more safety, so I think this is encouraging," Agarwal adds. "I think the main areas where oral contraceptives are likely to be safer are with stroke and heart attacks."
Another study is looking at this very thing. And, meanwhile, the current researchers will continue to collect data from this study.
More information
For more on oral contraceptives, visit Johns Hopkins University. For more on different birth-control methods, visit Planned Parenthood.
