Self-Worth is an over-arching evaluation of a person's sense of individual value. Self-worth, however, is an underappreciated concept. It has rarely been reported related to physiological data; we found no studies related to the menstrual cycle or ovulation. It is also unclear if Self-Worth is a stable trait or a variable state. We sought to discover if "Feeling of Self-Worth" (as recorded daily) was related to cycle phases and ovulation of spontaneous menstrual cycles (without hormonal contraception) in healthy premenopausal women over one-year in data from the Prospective Ovulation Cohort. Participating women were invited to complete the Menstrual Cycle Diary© (Diary©) daily; it describes cycle-related and other comprehensive everyday life experiences including negative moods as well as changes from each person's usual Feelings of Self-Worth. Women recorded their Feeling of Self-Worth on a 5-level ordinal scale as a letter translated to a number originally centered on their usual feeling (U = 3) with two higher and two lower (letters) levels. The validated Quantitative Basal Temperature© (QBT©) method was used to assess ovulation and luteal lengths. Fifty-three healthy, community dwelling, normal-weight, non-smoking premenopausal women mean age 33.9 (95% CI 32.4, 35.5) years old were studied. All participants were first required to document two consecutive normal-length (21-36 days) and normally ovulatory (luteal length ≥10 days) cycles before enrolment. Each participant completed the Diary© and QBT© records daily over a mean of 13 cycles (minimum = 8). During the study, cycle lengths were mean 28.04 (95% CI 27.80, 28.28) days with 71% of all cycles being normally ovulatory, 26% having short luteal phases (SLP, LL