NEW YORK, Jan 11 (Reuters Health) -- The newer, low-dose types of birth
control pills may be less likely to cause heart problems in female smokers than
older formulations of oral contraceptives, US researchers suggest.
In the study of women in their mid-20s, smokers who took an older type of
oral contraceptive had a higher blood pressure response to mental stress than
smokers who took newer pills, according to investigators at the University of
North Carolina at Chapel Hill.
Women who were taking the older oral contraceptives -- regardless of
smoking status -- had greater vascular resistance under stress, meaning that
their heart needed to work harder to pump blood through their vessels. The
report is published in the January issue of the journal Obstetrics and
Gynecology.
The study included 23 smokers and 23 nonsmokers who took either
second-generation oral contraceptives, which were introduced in the late 1970s
and contain a synthetic hormone called levonorgestrel, or third-generation oral
contraceptives, which contain desogestrel or norgestimate. The researchers
induced stress in the volunteers by having them perform rapid calculations,
prepare and present short speeches, and sit with a bag of ice held to their
foreheads for 2 minutes.
"Based on our findings, the type of progesterone should be an important
consideration when determining which oral contraceptives to take, especially
among women who continue to smoke," said study co-author Patrician Straneva in a
statement issued by the University of North Carolina. "For some women, the newer
contraceptives may impart less risk, but that's a choice that ultimately needs
to be made between a woman and her doctor," she noted.
High blood pressure and vascular resistance are established risk factors
for heart disease, the authors note. Some 22 million women in the US smoke, and
many of them take oral contraceptives, the researchers add.
Women should consult their doctor regarding the most appropriate oral
contraceptive, as third-generation oral contraceptives may not be for everyone,
the investigators caution. Third-generation oral contraceptives may increase the
risk of blood clots in certain women, especially those who are genetically
predisposed to clotting, they explain.
