Data from the Demographic and Health Surveys carried out in 12 African, Asian and Latin American countries show that in 10 of the countries, fewer than 22 percent of women have ever practiced periodic abstinence and fewer than seven percent currently practice that method. In Sri Lanka and Peru, however, 40 percent of women have used periodic abstinence, and 15 percent and 18 percent, respectively, are currently using the method. The vast majority of women who practice periodic abstinence use the calendar, or rhythm, technique to determine their fertile period; one-fourth to more than one-half of current users in seven countries report using an additional method (usually the condom or withdrawal) during the same month. The problem that women who have heard of periodic abstinence most often associate with that method is its ineffectiveness, and the most common reason users give for discontinuation is method failure. In every country, women who have ever practiced periodic abstinence are more likely than others to know when their fertile period is, but even among ever-users, knowledge is far from universal: Morocco, Sri Lanka, Colombia, the Dominican Republic, Ecuador, and Peru are the only countries where at least half of all women who are ever-users of periodic abstinence are able to correctly identify the fertile period.