Low-dose 'Pill' may have less stroke risk for young women.

2003 JUL 3 - (NewsRx.com & NewsRx.net) -- Newer, low-dose birth control pills seem to carry less stroke risk than high-dose pills for young women, but should be prescribed with care, according to an Australian study published in the June 13, 2003, rapid access issue of Stroke, a journal of the American Heart Association.

The oral contraceptive pill (OCP) was introduced in the 1960s and, nearly simultaneously, researchers raised the possibility that it might induce stroke, says lead author Sasitorn Siritho, MD. She conducted the study while a visiting research fellow at the National Stroke Research Institute, Austin & Repatriation Medical Centre in West Heidelberg, Australia.

"However, most studies that suggested an association between OCP use and stroke were done on formulations that typically contained 80 or 100 micrograms (mcg) of estrogen, much higher than the 30-35 mcg of estrogen in the pills commonly used today. Little research has focused only on the newer formulations and a good deal of controversy remains on this issue," she explains.

Researchers at four major Melbourne, Australia, hospitals matched 234 women (ages 15 to 55) who had a stroke between 1984 and 1996 to 234 controls recruited from the same streets as the stroke patients. Nurses conducted detailed personal interviews, obtained a list of previous and current medications used by the subjects, and details on family medical history.

The researchers found that women who reported currently using OCP with less than 50 mcg of estrogen seemed to be at no greater risk of ischemic stroke, the kind of stroke in which a blood clot blocks an artery supplying the brain. In addition, there was no association between the number of years a woman had taken OCP and the risk of stroke.

Although the odds ratio of stroke was 1.76 for women who used the low-estrogen OCP, that number did not reach the level of statistical significance, says coauthor Amanda G. Thrift, PhD, head of epidemiology at the Australian institute.

Women who reported having stroke-like ...