This technique can be used either as a method of contraception or to increase a woman's chances of getting pregnant. When used as contraception, this method involves a couple avoiding intercourse during the times that the woman is most likely to be fertile. This method requires that the woman be very aware of her own body and her reproductive cycle; some estimate that this method has a 70%-98% rate of success, depending on the regularity of the woman's cycle and the specific monitoring technique used. Signs that a woman has ovulated (and is therefore fertile) include a sudden change in basal body temperature, changes in vaginal mucus, or a combination of the two. A woman is least likely to be fertile during her menstrual period and for a few days thereafter. Fertility awareness is most often used by couples who don't want to use or who don't have access to other methods of contraception. It is also as a fertility enhancing method by couples who have had trouble with infertility.