Stroke guidelines now include risks that are unique to women.   The American Stroke Association, a division of the American Heart Association, released new stroke prevention guidelines this week for the first time in a decade. The focus of the guidelines is to provide primary prevention — or preventing strokes in those who have never had one — and includes a section on sex- and gender-specific factors contributing to stroke.   ASA lists sex-specific conditions like endometriosis and early menopause as risk factors for stroke. “Among those with endometriosis, studies have shown a consistently increased risk of stroke,” the guidelines read. “Young individuals with endometriosis are a subgroup who might benefit from enhanced attention to cardiovascular risk assessment and prevention strategies.”   A stroke is most often caused when a blood vessel in the brain is suddenly blocked by a blood clot, causing the nearby tissue to die due to lack of oxygen. More than 795,000 people in the United States have a stroke every year, with 1 in 6 deaths from cardiovascular disease caused by stroke, according to the Centers for Disease Control and Prevention. Research from the American Heart Association shows that strokes among young people have been on the rise for the past 30 years. Every year, between 10 percent to 15 percent of the roughly 795,000 people in the country who have a stroke are between the ages of 18 and 45, according to the AHA.  Those rising stroke rates could be linked to rising rates of diabetes, high blood pressure, obesity and physical inactivity in younger Americans, according to Joshua Willey, a stroke neurologist at New York-Presbyterian Hospital.   The guidelines also state that women using combined hormonal contraception — or birth control methods that contain both estrogen and progestin — are at a higher risk for stroke.    Women undergoing estrogen-based hormone therapy treatments are at some risk of cardiovascular disease, the guidelines note. Those risks are mainly linked to oral hormone therapy, while topical estrogen treatments are not associated with increased risk of stroke.