Extended cycle combined hormonal contraceptive Extended cycle combined hormonal contraceptive Extended or continuous cycle combined oral contraceptive pills are a packaging of combined oral contraceptive pills (COCPs) that reduce or eliminate the withdrawal bleeding that would occur once every 28 days in traditionally packaged COCPs. Extended cycle use of COCPs may also be called menstrual suppression. Other combined hormonal contraceptives (those containing both an estrogen and a progestin) may also be used in an extended or continuous cycle. For example, the NuvaRing vaginal ring and the contraceptive patch have been studied for extended cycle use, and the monthly combined injectable contraceptive may similarly eliminate bleeding.
Menstrual synchrony to menstrual synchrony, has been reported in several other mammalian species. Menstrual or estrous synchrony has been reported in other species including Norway rats, hamsters, chimpanzees, and Golden lion tamarins. In non-human primates, the term may also refer to the degree of overlap of menstrual or estrous cycles, which is the overlap of estrous or menses of two or more females in a group due, for example, to seasonal breeding. However, as with early human studies on menstrual synchrony, non-human estrous synchrony studies also were criticized for methodological problems. Subsequent studies failed to find estrous synchrony in rats, hamsters, chimpanzees,