Transitioning to the menopausal transition: a scoping review of research on the late reproductive stage in reproductive aging

IMPORTANCE AND OBJECTIVE: In 2001 Staging Reproductive Aging Workshop conferees described the late reproductive stage (LRS) of reproductive aging as preceding the onset of the menopausal transition, yet there has been little attention to this aspect of reproductive aging. The aim of this scoping review was to examine scientific publications characterizing the LRS to map what is known about this stage with particular focus on reproductive endocrine patterns, menstrual cycle changes, and symptoms. METHODS: The initial search strategy included PubMed and CINAHL searches for the phrase LRS and "human." Given a low yield of research articles, a second stage used "late reproductive age" (LRA) as a search term. These strategies yielded 9 and 26 research articles, respectively. Publications meeting inclusion criteria (data-based research studies, focus on LRS or LRA and hormonal patterns, menstrual characteristics, and symptoms) published in English were reviewed by coinvestigators. Excluded studies were related to specific diseases, such as cardiovascular disease, and treatment studies. Data were summarized using qualitative methods. To ensure adequate coverage of published research we expanded our review to a third phase in which we identified longitudinal studies of the menopausal transition. DISCUSSION AND CONCLUSIONS: Studies of the LRS focused on: symptoms (anxiety and mood symptoms, bladder symptoms, urinary incontinence, urinary frequency, and nocturia) and associated factors, such as endocrine levels and gene polymorphisms; symptom clusters women experienced during the LRS; cognitive function testing results; changing patterns of physiology such as cytokines and chemokines, lipids, hormone patterns/levels; and association of lifestyle factors such as smoking with hormone levels and symptoms. The LRA search yielded a preponderance of studies of reproductive hormones (such as anti-Mullerian hormone) and menstrual cycle patterns. Remaining studies focused on symptoms, gene variants, health-related behaviors and approaches to classifying menstrual cycles. Longitudinal studies revealed reports of symptoms as well as attempts to classify the progression from the reproductive years to the menopausal transition. Study of the LRS has not been systematic and the limited number and scope of completed studies have yet to contribute a clear and complete picture of the LRS. In some, LRS provided a comparison stage against which to evaluate menopausal transition hormonal and cycle patterns and symptoms. Harmonizing the results of studies of the LRS and LRA is essential to understand more completely women's experiences of the LRS and to allow clinicians to provide better support for women during this time. The LRS also represents an ideal inflection point to promote lifestyle choices that could alter the trajectories of chronic diseases that arise in the fifth, sixth, and seventh decades of women's lives.