Women are diagnosed with hypertension when a reading measures a systolic value greater than 140 milliliters of mercury and a diastolic value greater than 80 milliliters of mercury, according to Mayo Clinic. This criteria for diagnosing hypertension is the same for both men and women.
Systolic pressure measures pressure in the arteries when the heart beats. Diastolic pressure measures pressure in the arteries between beats, explains Mayo Clinic.
Up to 95 percent of reported hypertension in the United States has an unknown cause, according to WebMD. This is known as essential hypertension. Factors that increase the risk of essential hypertension include smoking, obesity, lack of exercise, too much salt and alcohol in the diet, stress and genetics. After age 65, black women report the highest incidence of hypertension in the United States, according to WebMD.