Study: New Type of the Pill Doesn’t Increase Clot Risk

The latest in a series of studies on the newest formulation of birth control pills published recently shows they do not increase the risk of blood clots.

The study, in the journal Contraception, shows second- and third-generation oral contraceptives carry the same risk of deep-vein thrombosis, or blood clots in the leg that can be carried to the lungs.

Michael Lewis and colleagues at Montreal’s McGill University and in the U.S., Germany and Britain studied some 2,200 women and found no increased risk in the new pills.

The third-generation pills were the focus of a worldwide scare in 1995, when several studies published in the Lancet medical journal found they tripled the risk of such blood clots.

Government regulators in Britain issued warnings about the pills, and they were followed by those in Germany and Norway. Sales of the pills, ironically formulated specifically to diminish health risks, plummeted in Europe.

The researchers, whose work was funded by pill-maker Schering AG, reanalyzed the data from those studies.

“We found, for first-time users, that the adjusted rate ratio of VTE [blood clots] as a function of the duration of oral contraceptive use is essentially identical for second- and third-generation pills relative to never users,” they wrote.

They said the first-time study used many women who had tried other pills before and who may have had problems with them.

They also found that the new pills did not increase the risk of heart attacks.

“Third-generation oral contraceptives are the first to be associated with no excess risk of [heart attack]” they wrote. “A significantly lower risk of [heart attack] is found when comparing use of third-generation oral contraceptives with use of second-generation oral contraceptives.”

They said more studies were needed to determine absolutely whether the new pills carried any different risks from older ones.

But Daniel Mishell, editor in chief of Contraception and chairman of the department of obstetrics and gynecology at USC, said the issue should soon be closed.

“These studies add to the database that fails to support the warnings about these particular formulations issued in 1995 by the United Kingdom, Germany and Norway,” he wrote in a commentary.

“We now have substantial data that these public health warnings were premature and that the use of third-generation products should not be restricted.”