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 study has ever found that menstrual cycles become strictly concordant, nevertheless "menstrual synchrony" is used to refer the phenomenon of menstrual cycle onsets becoming closer to each other over time. In a recent systematic review of menstrual synchrony, Harris and Vitzthum concluded, "In light of the lack of empirical evidence for MS [menstrual synchrony] "sensu stricto", it seems there should be more widespread doubt than acceptance of this hypothesis" (pp. 238–239). The experience of synchrony may be the result of the mathematical fact that menstrual cycles of different frequencies repeatedly converge and diverge over time and not due to a