Ultradian rhythms in heart rate variability and distal body temperature anticipate onset of\xa0the luteinizing hormone surge

Mark Newman,Lance J Kriegsfeld,Azure D Grant

doi:10.1038/s41598-020-76236-6

Abstract

The menstrual cycle is characterized by predictable patterns of physiological change across timescales. Although patterns of reproductive hormones across the menstrual cycle, particularly ultradian rhythms, are well described, monitoring these measures repeatedly to predict the preovulatory luteinizing hormone (LH) surge is not practical. In the present study, we explored whether non-invasive measures coupled to the reproductive system: high frequency distal body temperature (DBT), sleeping heart rate (HR), sleeping heart rate variability (HRV), and sleep timing, could be used to anticipate the preovulatory LH surge in women. To test this possibility, we used signal processing to examine these measures in 45 premenopausal and 10 perimenopausal cycles alongside dates of supra-surge threshold LH and menstruation. Additionally, urinary estradiol and progesterone metabolites were measured daily surrounding the LH surge in 20 cycles. Wavelet analysis revealed a consistent pattern of DBT and HRV ultradian rhythm (2–5 h) power that uniquely enabled anticipation of the LH surge at least 2 days prior to its onset in 100% of individuals. Together, the present findings reveal fluctuations in distal body temperature and heart rate variability that consistently anticipate the LH surge, suggesting that automated ultradian rhythm monitoring may provide a novel and convenient method for non-invasive fertility assessment.

Highlights

The menstrual cycle is characterized by predictable patterns of physiological change across timescales
The present findings reveal stereotyped fluctuations in distal body temperature (DBT) and heart rate variability (HRV) (RMSSD) UR power that anticipate 100% of luteinizing hormone (LH) surge onsets, a key component of female health and fertility
Changes in DBT circadian rhythm power were not predictive of the LH surge, suggesting that URs are uniquely coupled to the pre-ovulatory time of the menstrual cycle

Summary

Introduction

The menstrual cycle is characterized by predictable patterns of physiological change across timescales. We explored whether non-invasive measures coupled to the reproductive system: high frequency distal body temperature (DBT), sleeping heart rate (HR), sleeping heart rate variability (HRV), and sleep timing, could be used to anticipate the preovulatory LH surge in women. The most widely used method, female hormonal contraception, has short and long term risks for many users, including increased breast cancer r ate[3,4], luteal phase deficiency5, dysmenorrhea[5,6], altered c ognition[7,8], and depressed mood[9,10] These risks, combined with increasing recognition that many physiological systems vary in a structured manner across the menstrual cycle[11,12,13,14], provide the impetus to develop FAM approaches that employ high-temporal-resolution, non-invasive measures of physiology. Assessment of these peripheral measures could, potentially enable endocrine status assessment via timeseries a nalysis[14,23,56]

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Conclusion