How do different types of premenstrual symptoms change during the menstrual cycle?

BACKGROUND Premenstrual symptoms are distressing and impairing for individuals and costly to society. These symptoms are heterogeneous within and across people, and they are dimensional, occurring on a spectrum. Furthermore, premenstrual symptoms are inherently dynamic—changing over the menstrual cycle and peaking perimenstrually. Understanding how symptom trajectories change over time may help us understand why symptoms occur. OBJECTIVE The first goal of this study was to enhance our understanding of the covariation among symptoms over the course of the menstrual cycle. We also sought to characterize the trajectories of these symptoms in a novel way, and use these characteristics to hypothesize about why symptoms might take different courses. METHODS A sample of female undergraduates (N=85) who reported no use of hormonal birth control and regularly occurring menstrual periods were recruited for a four month-long electronic daily diary study of premenstrual symptoms. We explored the covariation of symptoms over the cycle by conducting a multilevel exploratory factor analysis of the daily diary items. Next, we characterized the trajectories of each symptom domain using multilevel natural spline models and their first/second derivatives. RESULTS We identified six distinct but correlated symptom domains at the within-person level which were affective, cognitive, interpersonal, pain, and somatic. In the natural spline models, we found that somatic symptoms increased/decreased more sharply and quickly than other symptom domains, pointing to a unique trajectory. Interpersonal and affective symptoms, on the other hand, were milder throughout. CONCLUSIONS Natural splines offer a novel and unique way to investigate trajectories of menstrual cycle symptoms over time. Our findings highlight the importance of including menstrual cycle variables in daily diary studies, and underscore the need for more research on how to effectively model the impact of the menstrual cycle on mood and behavior in non-clinical samples.

Reproduced under CC-BY.