Modern fertility awareness methods: wrist wearables capture the changes in temperature associated with the menstrual cycle

Core and peripheral body temperatures are affected by changes in reproductive hormones during the menstrual cycle. Women worldwide use the basal body temperature (BBT) method to aid and prevent conception. However, prior research suggests that taking one’s daily temperature can prove inconvenient and subject to environmental factors. We investigate whether a more automatic, non-invasive temperature measurement system can detect changes in temperature across the menstrual cycle. We examined how wrist skin temperature (WST), measured with wearable sensors, correlates with urinary tests of ovulation and may serve as a new method of fertility tracking. One hundred and thirty-six eumenorrheic, non-pregnant women participated in an observational study. Participants wore WST biosensors during sleep and reported their daily activities. An at-home luteinizing hormone (LH) test was used to confirm ovulation. WST was recorded across 437 cycles (mean cycles/participant = 3.21, S.D. = 2.25). We tested the relationship between the fertile window and WST temperature shifts, using the BBT three-over-six rule. A sustained 3-day temperature shift was observed in 357/437 cycles (82%), with the lowest cycle temperature occurring in the fertile window 41% of the time. Most temporal shifts (307/357, 86%) occurred on ovulation day (OV) or later. The average early-luteal phase temperature was 0.33°C higher than in the fertile window. Menstrual cycle changes in WST were impervious to lifestyle factors, like having sex, alcohol, or eating prior to bed, that, in prior work, have been shown to obfuscate BBT readings. Although currently costlier than BBT, the present study suggests that WST could be a promising, convenient parameter for future multiparameter fertility awareness methods.

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Ultradian Rhythms in Heart Rate Variability and Distal Body Temperature Anticipate the Luteinizing Hormone Surge Onset

10.1101/2020.07.15.205450 ◽

2020 ◽

Author(s):

Azure D. Grant ◽

Mark Newman ◽

Lance J. Kriegsfeld

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Menstrual Cycle ◽

Body Temperature ◽

Inflection Point ◽

Ultradian Rhythms ◽

Fertility Awareness ◽

Lh Surge ◽

Non Invasive ◽

Sleep Timing

AbstractThe human menstrual cycle is characterized by predictable patterns of physiological change across timescales, yet non-invasive anticipation of key events is not yet possible at individual resolution. Although patterns of reproductive hormones across the menstrual cycle have been well characterized, monitoring these measures repeatedly to anticipate the preovulatory luteinizing hormone (LH) surge is not practical for fertility awareness. In the present study, we explored whether non-invasive and high frequency measures of 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 across the menstrual cycle. Cycles were examined from both pre- (n=45 cycles) and perimenopausal (n=10 cycles) women using days of supra-surge threshold LH and dates of menstruation for all cycles. For a subset of cycles, urinary estradiol and progesterone metabolites were measured daily around the time of the LH surge. Wavelet analysis revealed a consistent inflection point of ultradian rhythm (2-5 h) power of DBT and HRV that enabled anticipation of the LH surge at least 2 days prior to its onset in 100% of individuals. In contrast, the power of ultradian rhythms in heart rate, circadian rhythms in body temperature, and metrics of sleep duration and sleep timing were not predictive of the LH surge. Together, the present findings reveal fluctuations in distal body temperature and heart rate variability that consistently anticipate the LH surge and may aid in fertility awareness.Key PointsUltradian (2-5 h) rhythm power of distal body temperature and heart rate variability (RMSSD) exhibits a stereotyped inflection point and peak in the days leading up to the LH surge in premenopausal women.Circadian rhythms of distal body temperature and single time-point/day metrics do not permit anticipation of the LH surge.Measurement of continuous metabolic and autonomic outputs, enabling assessment of ultradian rhythms, may be of value to the fertility awareness method.

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A cross-sectional study of fertile period awareness, knowledge, attitudes and practice in infertile couples seeking fertility assistance

International Journal of Reproduction Contraception Obstetrics and Gynecology ◽

10.18203/2320-1770.ijrcog20183787 ◽

2018 ◽

Vol 7 (9) ◽

pp. 3744

Author(s):

Shilpa Pankaj Kshrisagar ◽

Arti Sidharth Shirsath

Keyword(s):

Menstrual Cycle ◽

Cross Sectional Study ◽

Fertile Period ◽

Cross Sectional ◽

Fertility Awareness ◽

Medical Interventions ◽

Medical College ◽

Loss Of Self ◽

Fertile Window ◽

Infertile Couples

Background: Infertility is one of the most distressful condition for a couple. Medical interventions may exacerbate anxiety, depression, stress, loss of self-esteem, guilt and grief in these couples. But many studies indicate that most cases of infertility can be attributed to a physiological cause in the man or woman. Previous research has suggested that poor fertility period awareness may be a contributing cause of infertility among couples seeking assistance at infertility clinics. The actual practices and attitudes towards fertility-awareness in this particular group of patients are unknown and need to be explored. The aim of the present study was to report the study of fertile period awareness and their knowledge, attitude and practice in the infertile couples seeking fertility assistanceMethods: This is a cross-sectional questionnaire-based study. The study was conducted over a period of 6 months from June to December 2017 in the couples attending the infertility clinic at Smt Kashibai Navale Medical College and General Hospital, Pune.Results: Total 246 of 280 distributed questionnaires were completed (response rate =87.8%). Out of these 60% (n=147) believed they had timed intercourse within the fertile window of the menstrual cycle in their attempts at conception, but surprisingly only 36%(n=52) could accurately identify this window. In this study 23% (n=56) participants had already taken prior treatment but still 50% were ignorant about fertile window. It was shocking that among 246 only 15% (n=38) couples were actually practising fertile period due to some reasons and most of them did not know or rely upon the concept of fertile period. Almost 94% of them believed that they should receive fertility-awareness education when they ﬁrst report trouble in conceiving to their doctor.Conclusions: Most couples seeking assistance at infertility clinics were unaware of the fertile window of the menstrual cycle and only few could accurately identify this window, suggesting that poor fertility awareness may be a contributing cause of infertility.

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

Scientific Reports ◽

10.1038/s41598-020-76236-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Azure D. Grant ◽

Mark Newman ◽

Lance J. Kriegsfeld

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Menstrual Cycle ◽

Body Temperature ◽

Luteinizing Hormone ◽

Reproductive Hormones ◽

Ultradian Rhythm ◽

Ultradian Rhythms ◽

Lh Surge ◽

Non Invasive

AbstractThe 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.

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Point-of-Care Testing Using Invasive and Non-Invasive Hemoglobinometers: Reliable and Valid Method for Estimation of Hemoglobin among Children 6–59 Months

Journal of Tropical Pediatrics ◽

10.1093/tropej/fmaa111 ◽

2020 ◽

Author(s):

Gomathi Ramaswamy ◽

Kashish Vohra ◽

Kapil Yadav ◽

Ravneet Kaur ◽

Tripti Rai ◽

...

Keyword(s):

Point Of Care ◽

Venous Blood ◽

Public Health Problem ◽

Outpatient Department ◽

Point Of Care Testing ◽

Adequate Treatment ◽

Non Invasive ◽

Hematology Analyzer ◽

The Mean ◽

Study Participants

Abstract Introduction Globally around 47.4% of children and in India, 58% of children aged 6–59 months are anemic. Diagnosis of anemia in children using accurate technologies and providing adequate treatment is essential to reduce the burden of anemia. Point-of-care testing (POCT) devices is a potential option for estimation of hemoglobin in peripheral and field settings were the hematology analyzer and laboratory services are not available. Objectives To access the validity of the POCTs (invasive and non-invasive devices) for estimation of hemoglobin among children aged 6–59 months compared with hematology analyzer. Methods The study participants were enrolled from the pediatric outpatient department in Haryana, India, from November 2019 to January 2020. Hemoglobin levels of the study participants were estimated in Sahli’s hemoglobinometer and invasive digital hemoglobinometers (DHs) using capillary blood samples. Hemoglobin levels in non-invasive DH were assessed from the finger/toe of the children. Hemoglobin levels measured in POCTs were compared against the venous blood hemoglobin estimated in the hematology analyzer. Results A total of 120 children were enrolled. The mean (SD) of hemoglobin (g/dl) estimated in auto-analyzer was 9.4 (1.8), Sahli’s hemoglobinometer was 9.2 (1.9), invasive DH was 9.7 (1.9), and non-invasive DH was 11.9 (1.5). Sahli’s hemoglobinometer (95.5%) and invasive DH (92.2%) had high sensitivity for the diagnosis of anemia compared with non-invasive DH (24.4%). In contrast, non-invasive DH had higher specificity (96.7%) compared with invasive DH (83.3%) and Sahli’s hemoglobinometer (70%). Invasive DH took the least time (2–3 min) for estimation of hemoglobin per participant, followed by Sahli’s (4–5 min) and non-invasive DH (5–7 min). Conclusion All three POCT devices used in this study are reasonable and feasible for estimating hemoglobin in under-5 children. Invasive DHs are potential POCT devices for diagnosis of anemia among under-5 children, while Sahli’s can be considered as a possible option, where trained and skilled technicians are available. Further research and development are required in non-invasive DH to improve accuracy. Lay summary In India, anemia is a serious public health problem, where 58% of the children aged 6–59 months are anemic. Point-of-care testing (POCT) using digital hemoglobinometers (DHs) has been recommended as one of the key interventions by the Anemia Mukt Bharat program since 2018 in India. These POCT devices are easy to use, less invasive, can be carried to field, require minimal training and results are available immediately. Therefore this study assessed the validity of POCT devices—invasive DH, non-invasive DH and Sahli’s hemoglobinometer among 6–59 months children in facility setting compared with the gold standard hematology analyzer. A total of 120 children under 6–59 months of age were enrolled from the pediatric outpatient department in Haryana, India, from November 2019 to January 2020. The (mean hemoglobin in g/dl) invasive (9.7) and non-invasive DH (11.9) overestimated hemoglobin value, while Sahli’s (9.2) underestimated hemoglobin compared with hematology analyzer (9.4). Invasive DH (92.2%) and Sahli’s hemoglobinometer (95.5%) reported high ability to correctly identify those with anemia compared with non-invasive DH (24.4%). In contrast, non-invasive DH (96.73%) had higher ability to correctly identify those without the anemia compared with invasive DH (83.3%) and Sahli’s (70%).

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Recent Advances in Wearable Devices for Non-Invasive Sensing

Applied Sciences ◽

10.3390/app11031235 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1235

Author(s):

Su Min Yun ◽

Moohyun Kim ◽

Yong Won Kwon ◽

Hyobeom Kim ◽

Mi Jung Kim ◽

...

Keyword(s):

Health Monitoring ◽

Data Transmission ◽

Wearable Sensors ◽

Wearable Devices ◽

Wireless Power ◽

Non Invasive ◽

Sensing Systems ◽

Recent Advances ◽

Wearable Systems ◽

Precise Diagnosis

The development of wearable sensors is aimed at enabling continuous real-time health monitoring, which leads to timely and precise diagnosis anytime and anywhere. Unlike conventional wearable sensors that are somewhat bulky, rigid, and planar, research for next-generation wearable sensors has been focused on establishing fully-wearable systems. To attain such excellent wearability while providing accurate and reliable measurements, fabrication strategies should include (1) proper choices of materials and structural designs, (2) constructing efficient wireless power and data transmission systems, and (3) developing highly-integrated sensing systems. Herein, we discuss recent advances in wearable devices for non-invasive sensing, with focuses on materials design, nano/microfabrication, sensors, wireless technologies, and the integration of those.

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Twice-Daily Subcutaneous Injection of Kisspeptin-54 Does Not Abolish Menstrual Cyclicity in Healthy Female Volunteers

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2013-1069 ◽

2013 ◽

Vol 98 (11) ◽

pp. 4464-4474 ◽

Cited By ~ 19

Author(s):

C. N. Jayasena ◽

A. N. Comninos ◽

G. M. K. Nijher ◽

A. Abbara ◽

A. De Silva ◽

...

Keyword(s):

Menstrual Cycle ◽

Reproductive Function ◽

Reproductive Hormones ◽

Follicular Phase ◽

Hypothalamic Amenorrhea ◽

Healthy Women ◽

Lh Pulsatility ◽

Serum Lh ◽

Healthy Female ◽

Ultrasound Parameters

Background: Kisspeptin is a critical hypothalamic regulator of reproductive function. Chronic kisspeptin administration causes profound tachyphylaxis in male monkeys and in women with functional hypothalamic amenorrhea. The pharmacological effects of chronic kisspeptin exposure in healthy women with normal menstrual cycles have not been studied previously. Aim: Our aim was to determine the effects of follicular-phase kisspeptin-54 treatment on menstrual cyclicity in healthy women. Methods: We performed a prospective, single-blinded, 1-way crossover study. Healthy women received twice-daily sc injections of kisspeptin (6.4 nmol/kg) or 0.9% saline during menstrual days 7–14 (n = 5 per treatment arm). Serial assessments of basal reproductive hormones, ultrasound parameters, LH pulsatility, and acute sensitivity to GnRH and kisspeptin-54 injection were performed. Results: Menstrual cyclicity persisted in all women after follicular-phase kisspeptin-54 treatment. Chronic exposure to kisspeptin-54 did not abolish acute stimulation of LH after injection of kisspeptin-54 or GnRH. In addition, kisspeptin-54 treatment was associated with a shorter mean length of the menstrual cycle (mean length of menstrual cycle was 28.6 ± 1.4 days with saline vs 26.8 ± 3.1 days with kisspeptin, P < .01), earlier onset of highest recorded serum LH (mean menstrual day of highest LH was 15.2 ± 1.3 with saline vs 13.0 ± 1.9 with kisspeptin, P < .05), and earlier onset of the luteal phase (mean menstrual day of progesterone increase was 18.0 ± 2.1 with saline vs 15.8 ± 0.9 with kisspeptin, P < .05). Conclusion: Our data suggest that 1 week of exogenous kisspeptin-54 does not abolish menstrual cyclicity in healthy women. Further work is needed to determine whether kisspeptin could be used to treat certain anovulatory disorders.

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P–469 Period Tracker Applications – are they giving women accurate menstrual cycle information?

Human Reproduction ◽

10.1093/humrep/deab130.468 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

L Worsfold ◽

L Marriott ◽

S Johnson ◽

J Harper

Keyword(s):

Menstrual Cycle ◽

Cycle Length ◽

Data Entry ◽

Accurate Information ◽

Menstrual Cycles ◽

Conflicting Information ◽

Search Terms ◽

Fertile Window ◽

Registration Number ◽

Almost All

Abstract Study question Are period trackers giving women accurate information about their periods and ovulation? Summary answer The top 10 period trackers gave conflicting information on period dates, ovulation day and the fertile window. What is known already Period tracking applications allow women to track their menstrual cycles and receive a prediction for their periods. The majority of applications also provide predictions of day of ovulation and the fertile window. Previous research indicates applications are basing predictions on assuming women undergo a textbook 28-day cycle with ovulation occurring on day 14 and a fertile window between days 10 and 17. Study design, size, duration An audit of menstrual cycle apps was conducted on the Apple app store using menstrual cycle tracker/period tracker as the search terms. The top ten apps that followed the inclusion and exclusion criteria were analysed and used for this study. All apps had the ability to allow retrospective data entry giving future cycle predictions and fertile window, and nine of the apps predicted a day of ovulation. Participants/materials, setting, methods Five women’s profiles for 6 menstrual cycles were created and entered into each app. Cycle length (CL) and ovulation day (OD) for the 6th cycle were; Woman 1 – Constant 28 day CL, 0D 16, Woman 2 – Average 23 day CL, OD 13, Woman 3 – Average 28 day CL, OD 17, Woman 4 – Average 33 day CL, OD 20 and Woman 5 – Irregular, average 31 day CL, OD 14. Main results and the role of chance For cycle length, the apps all predicted woman 1’s cycles correctly but for women 2–5, the apps predicted 0 to 8 days shorter or longer than expected. For day of ovulation; for woman 1, no apps predicted this correctly; the apps ranged from day 13–15. For woman 2, 1 app was correct and overall the apps showed a lot of variation from day 8 to 13. For woman 3, no apps got it right, with a range of day 13–16. For woman 4, 2 apps got it right, but the apps ranged from day 13–20. For woman 5, no apps got right; the apps ranged from day 13–21. Irrespective of cycle length, 7 apps predicted a fertile window of 7 days in almost all cases; except 1 app that predicted 6 days for woman 2 and a different app which predicted 8 days for woman 4. For the remaining 3 apps, one always predicted a 10 day fertile window. One app predicted an 11 day fertile window in 4/5 women. One app predicted a 12 day fertile window in 4/5 women. Limitations, reasons for caution The five profiles created spanned a range of observed cycle characteristics, but many permutations are possible. A Monte Carlo type analysis could be conducted to examine these possibilities to provide more precise assessment of app performance, but as data had to be added manually into apps, this was not possible. Wider implications of the findings: The apps do not use the same algorithm and show variation. The information given by these apps is not 100% accurate, especially for the day of ovulation and the fertile window which can only be predicted if using a marker of ovulation, such as basal body temperature or ovulation sticks. Trial registration number Not applicable

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Sex and Conception Probability

10.1093/acrefore/9780190632366.013.179 ◽

2021 ◽

Author(s):

Justin C. Konje ◽

Oladipo A. Ladipo

Keyword(s):

Menstrual Cycle ◽

Sexual Intercourse ◽

Time Window ◽

Continuous Process ◽

Female Genital Tract ◽

Human Reproduction ◽

Current Evidence ◽

Fertile Window ◽

Time Period ◽

The Impact

Central to the survival of any species is the ability to procreate. In most cases, procreation is sexual, involving a process that ensures appropriate and timed contact between the male and female gametes. Successful human reproduction is premised on sexual intercourse occurring at a time when there is a receptive endometrium as well as an ovum ready for fertilization by spermatozoa. This time window of the menstrual cycle known as the fertile or fecund window is poorly defined and highly variable from one individual to another. Furthermore, while spermatogenesis is a continuous process, the impact of too frequent intercourse (defined as that occurring more than every 2 to 3 days) on fertilization has often been thought to be associated with a decreased fertilization potential of spermatozoa. Current evidence challenges previously held views on the fertile window and how it is determined, the timing of intercourse and how it is related to conception and miscarriages, the length of the luteal phase, and the precise time period during which the chances of fertilization are highest in any given menstrual cycle. The ability of spermatozoa to survive in the female genital tract for 5 days means fertilization can occur up to 5 days from sexual intercourse. During each menstrual cycle, there is a window of 5 to 6 days for fertilization to occur, and this period is defined not by the length of the cycle but by the timing of ovulation, with the chances of fertilization highest with intercourse occurring 1 to 2 days before ovulation.

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