High Blood Pressure:

Although in itself not a life threatening condition, Pill­related high blood pressure—experienced by up to 5 percent of women taking high­dose pills—can lead to heart disease and stroke. If your blood pressure is over 140/90, you should stop taking OCs until it is under control. All women using the Pill should have their blood pressure checked once a year; for women with a history of blood pressure problems, a check once every six months is probably in order.