Objectives: To explore the experience of reproductive-age women in the French population with premenstrual syndrome (PMS) by estimating perceived symptom prevalence, identifying risk factors, and quantifying the burden of symptoms. This study also assesses the stability of the PMS diagnosis over a one-year period of follow-up. Methods: The prevalence of reported PMS was estimated from a population-based cohort of 2863 French women interviewed in 2003 and 2004. Multivariate logistic regressions were used to identify risk factors associated with PMS. PMS fluctuation was studied by comparing women’s responses in 2003 and 2004. Results: Results show that 4.1% of women qualified for severe PMS (six symptoms) and 8.1% qualified for moderate PMS (one to five symptoms), resulting in 12.2% of women who reported PMS symptoms that impacted their daily lives. Risk factors for PMS fell into three categories: hormonal, psychosocial, and physiological, with life stressors and exogenous hormonal exposure exerting the most substantial impact. Results also indicate a high level of intra-individual variation in PMS status over time; among women who qualified for PMS during one or both years of the study, 72% demonstrated fluctuation in their PMS status. Conclusions: More women report suffering from distressing premenstrual symptoms than are captured by strict premenstrual dysphoric disorder (PMDD) diagnostic criteria. The impact of PMS symptoms on women appears to fluctuate over time, however, producing greater variability in the syndrome than previously recognized. Clinicians should be mindful of high intra-individual variability in the syndrome when advising patients about long-term management.