Elsevier

Fertility and Sterility

Volume 102, Issue 6, December 2014, Pages 1708-1715.e1
Fertility and Sterility

Original article
Magnitude of the impact of hot flashes on sleep in perimenopausal women

https://doi.org/10.1016/j.fertnstert.2014.08.016Get rights and content

Objective

To quantify the impact of objectively recorded hot flashes on objective sleep in perimenopausal women.

Design

Cross-sectional study. Participants underwent 1–5 laboratory-based polysomnographic recordings for a total of 63 nights, including sternal skin-conductance measures, from which 222 hot flashes were identified according to established criteria. Data were analyzed with hierarchical mixed-effect models and Spearman's rank correlations.

Setting

Sleep laboratory.

Patient(s)

Thirty-four perimenopausal women (age ± SD: 50.4 ± 2.7 years).

Intervention(s)

None.

Main Outcome Measure(s)

Perceived and polysomnographic sleep measures (sleep quality, amount of time spent awake after sleep onset, and number of awakenings). Subjective (frequency and level of bother) and objective (frequency and amount of hot flash–associated awake time) hot-flash measures.

Result(s)

Women had an average of 3.5 (95% confidence interval: 2.8–4.2, range = 1–9) objective hot flashes per night. A total of 69.4% of hot flashes were associated with an awakening. Hot flash–associated time awake per night was, on average, 16.6 minutes (95% confidence interval: 10.8–22.4 minutes), which accounted for 27.2% (SD 27.1) of total awake time per night. Hot flash–associated time awake, but not hot flash frequency, was negatively associated with sleep efficiency and positively associated with waking after sleep onset. In addition, self-reported wakefulness correlated with hot flash–associated waking, suggesting that women's estimates of wakefulness are influenced by the amount of time spent awake in association with hot flashes during the night. Having more perceived and bothersome hot flashes was correlated with more perceived wakefulness and awakenings and more objective hot flash–associated time awake and hot-flash frequency.

Conclusion(s)

The presence of physiological hot flashes accounts for a significant proportion of total objective time awake during the night in perimenopausal women.

Section snippets

Participants

Perimenopausal women were recruited from the San Francisco Bay Area community over a 4-year period. Women included here were participating in an ongoing study about sleep quality during the menopausal transition. The study was reviewed and approved by the SRI International Institutional Review Board, and all participants provided written, informed consent. Screening procedures for the study are fully described elsewhere (8).

All women were perimenopausal based on self-reported menstrual-cycle

Estradiol and FSH Concentrations

Women had E2 (34.7 ± 30.3 pg.ml−1, 95% CI [23.9, 41.2], n = 28) and FSH (48.9 ± 43.5 IU.l−1, 95% CI [34.4, 59.2], n = 28) levels consistent with being perimenopausal.

Quantification of Subjective and Objective Hot-Flash and Sleep Measures

Periods of being awake associated with hot flashes accounted for, on average, 27.2% of WASO on a given night, with a wide range between nights of 0%–89% (Fig. 2). An awakening was triggered during hot-flash onset in 69.4% of the 222 hot flashes identified. A total of 19.8% of hot flashes occurred without disturbing sleep in our

Discussion

We found that hot flash–associated time awake accounted for, on average, 27.2% of PSG-defined wakefulness during the night in perimenopausal women. As expected, having a greater number of objective hot flashes was correlated with a greater amount of hot flash–associated wakefulness. This index provides a measure of the magnitude of the effect of hot flashes on sleep, taking into account that not all hot flashes are associated with awakenings and that hot flashes are associated with a variable

Acknowledgments

The authors thank Justin Greco, Rebecca Carr, David Sugarbaker, David Dresser, Stephanie Claudatos, Sarah Inkelis, and Ben Mayer for their efforts in the data-collection process.

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  • Cited by (0)

    M.d.Z. has nothing to disclose. I.M.C. reports grants (and pending grants) with Apnicure Inc. H.S.J. has nothing to disclose. F.C.B. has nothing to disclose.

    This study's blood sample analysis was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (Specialized Cooperative Centers Program in Reproduction and Infertility Research) grant U54-HD28934, University of Virginia Center for Research in Reproduction Ligand Assay and Analysis Core; and National Institutes of Health grant HL103688 to F.C.B.

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