The progression of physiological phases, occurring in the endometrium during the estrous cycle that recur at regular intervals during the reproductive years. The estrous cycle is an ovulation cycle where the endometrium is resorbed if pregnancy does not occur.
Comment:
Note that this term should not be used for direct annotation. If you are trying to make an annotation to x phase, it is likely that the correct annotation is 'regulation of x/y phase transition' or to a process which occurs during the reported phase. To capture the phase when a specific location or process is observed, the phase term can be used in an annotation extension (PMID:24885854) applied to a cellular component term (with the relation exists_during) or a biological process term (with the relation happens_during).