Popular contraceptive linked to vascular dysfunction
DALLASLong-term use of a contraceptive injected once every three months impairs the arteries ability to contract and expand, possibly increasing the risk for heart disease, according to a report in the Sept. 3 rapid-access issue of Circulation: Journal of the American Heart Association.
Researchers studied depot medroxyprogesterone acetate (DMPA), commonly known by the brand name Dep-Provera. The drug affects the arteries ability to respond to different stimuli and particularly affects the ability of the artery to dilate, says Dudley J. Pennell, M.D., a professor of cardiology at the Imperial College School of Medicine in London. Problems with arterial response can reduce blood flow, which can damage the heart.
DMPA had been considered a good drug for women who may have some cardiac risk factors such as smoking or high blood pressure or a family history of heart disease, Pennell says. But the new findings suggest that women with cardiovascular disease risk factors would be wise to review that decision with their physician.
Pennell and colleagues measured vascular function in women who used DMPA for at least a year and compared the results to those of women who didnt use DMPA. They evaluated vascular function by measuring changes in the brachial artery using cardiovascular magnetic resonance imaging (CMR).
Twelve women taking DMPA and nien controls completed two brachial artery evaluations by CMR. Researchers evaluated the DMPA group at the end of a three-month DMPA cycle and within 48 hours of a new DMPA injection. They evaluated controls during the first 1-3 days of a menstrual cycle and again when the women were ovulating.
DMPA blocks hormonal signals that activate ovulation, so women using DMPA have very low circulating levels of estradiol, the estrogen produced by ovaries. In the controls, CMR studies were done when circulating levels of estradiol would be lowest (during menstruation) and highest (during ovulation). The DMPA women were evaluated when the estrogen-blocking contraceptive would be at its lowest and highest concentrations in the blood.