The Influence of the Menstrual Phases on Polysomnography

Abstract

Purpose: The primary objective of this study is to determine how the phases of the menstrual cycle influence the results of polysomnography (PSG).

Methods: Twenty-eight adult subjects who reported regular menstrual periods, last menstrual period (LMP) within 26 days of their PSG, no exogenous hormone use, no history of polycystic ovarian syndrome, and who were scheduled for diagnostic PSG at Boston Medical satisfied inclusion criteria for the study. These subjects were divided into a Follicular Cohort (days 0-13 of the cycle) or Luteal Cohort (days 14-26 of the cycle), and a one-way analysis using a t-test was performed to test the hypothesis that the follicular phase confers protection against obstructive sleep apnea (OSA). A likelihood-ratio chi-square test was also applied to assess for a statistically significant association between menstrual stage and the presence of moderate-to-severe sleep apnea (apnea-hypopnea index (AHI) > 15/h). Thus, the statistical analysis was performed using AHI as both a continuous and a categorical outcome.

Results: The mean AHI for patients in the Follicular Cohort (6.1/h) was significantly lower than the Luteal Cohort (14.3/h, p = 0.033). In the Follicular Cohort, 12% of patients had moderate to severe OSA. In the Luteal Cohort, 46% of patients had moderate to severe OSA (p = 0.045).

Conclusions: Subjects undergoing PSG during the follicular phase have significantly lower AHIs than those in the luteal phase. Thus, the timing of PSG acquisition for regularly menstruating women should be considered when interpreting results.

Keywords: menstrual cycle; obstructive sleep apnea; polysomnography.

Figure 1. Mean Overall AHI in Follicular Cohort (Left) vs. Luteal Cohort (Right).

A one-way t-test was used to evaluate whether reduced Total AHI (apnea-hypopnea index) shares a statistically significant correlation with escalating estrogen during the follicular phase of the menstrual cycle. This one-way analysis confirms a statistically significant difference between the mean Total AHIs in the follicular versus luteal groups (p=0.033). Horizontal solid bars represent the mean Total AHI within each group. The error bars and standard deviations are shown for each mean. The horizontal dashed line represents the mean Total AHI of all subjects.