Effects of Menstrual Cycle on Working Memory and its Correlation with Menstrual Distress Score: A Cross-sectional Study

Introduction: The menstrual cycle is a well known physiological model to study the ovarian steroid hormones, influencing cognitive functions like Working Memory (WM). Hormonal fluctuation during the menstrual cycle also affects menstrual distress-related symptoms, which indecently could the cognitive functions. However, the data were inconclusive regarding the change in WM functions during different phases of the menstrual cycle and the correlation of various WM functions with menstrual distress-related symptoms.

Aim: To examine the verbal and visuospatial WM functions during the proliferative (day 10-14) and secretory phase (day 21-25) of the menstrual cycle and to correlate various WM functions with menstrual distress symptoms scores.

Materials and Methods: A cross-sectional, observational study was carried out in the Department of Physiology at VMMC and Safdarjung Hospital, New Delhi, India, over a period of 18 months, from November 2020 to May 2022. A total of 40 young adult females with a history of regular menstrual cycles were selected for the study. Computerised software-based dual-task n-back WM tasks were given twice in the same menstrual cycle: first, the proliferative (day 10-14) and second, the secretory phase (day 21-25). In addition, a standardised Menstrual Distress Questionnaire (MDQ) based on various menstrual distress symptoms was also administered to each subject after completion of the WM task, first in the proliferative (day 10-14) and second, in the secretory phase (day 21-25). Based on MDQ, a score was calculated, a Menstrual Distress Score (MDS). Descriptive statistics such as mean, median, standard deviation, and mode were calculated and Pearson’s coefficient/Spearman’s rank correlation coefficient was used to assess the correlation WM parameters with MDS. Data was compiled and analysed using the statistical software Graph PadPrism.

Results: The mean age of the study population was 23.4 years with an average menstrual cycle length of 30 days. In the WM task, the ‘overall proportion of correct’ responses across all the tasks were significantly better in the secretory phase of the menstrual cycle than in the proliferative phase (p-value=0.040). Similarly, significantly improved performance in WM tasks during the secretory phase was also seen in the overall ‘hit rate’ of the visual target (p-value=0.020) and auditory targets (p-value=0.044). On the other hand, the correlation of WM parameters with MDS did not show any statistical significance except a significant negative correlation (r-value -0.369; p-value=0.019) between the ‘parametric sensitivity’ (subject’s ability to correctly distinguishing a target from a non target) of auditory WM of secretory phase and MDS of the proliferative phase.

Conclusion: The visual and auditory WM skills were significantly improved during the secretory phase compared to the menstrual cycle’s proliferative phases in terms of the target ‘hit rate’. However, increased MDS had no significant detrimental effect on the performance of WM tasks during the normal menstrual cycle.