Premenstrual symptoms: delineating symptom clusters.

The purposes of this study were to (1) identify the clusters of symptoms women experience during the premenstruum, (2) assess the reliability of the symptom clusters as reported by a population-based sample and a sample of women with three perimenstrual symptom patterns, (3) compare the levels of severity for the symptom clusters across menstrual cycle phases and by symptom patterns (e.g., premenstrual syndrome [PMS] vs. low severity), and (4) estimate the stability of the symptom cluster rankings across three menstrual cycle phases. Data from a cross-sectional population-based sample and a comparative sample of women screened for low-severity (LS), PMS, and premenstrual magnification (PMM) symptom patterns were analyzed using factor analysis, correlation coefficients, multivariate analysis of variance, and reliability and stability coefficients. Four symptom clusters accounted for >40% of the variance: turmoil, fluid retention, somatic symptoms, and arousal symptoms. Alpha (alpha) levels were >.70 for turmoil and fluid retention. None of the symptom clusters had correlations with other factors that exceeded a levels for sample 2. Symptom cluster scores varied by cycle phase and group (LS, PMS, PMM). Arousal and somatic symptoms were the most stable of the symptom clusters across cycle phases, and fluid retention and turmoil symptoms were less stable.