The Accuracy of Wrist Skin Temperature in Detecting Ovulation Compared to Basal Body Temperature: Prospective Comparative Diagnostic Accuracy Study

Abstract

Background As a daily point measurement, basal body temperature (BBT) might not be able to capture the temperature shift in the menstrual cycle because a single temperature measurement is present on the sliding scale of the circadian rhythm. Wrist skin temperature measured continuously during sleep has the potential to overcome this limitation. Objective This study compares the diagnostic accuracy of these two temperatures for detecting ovulation and to investigate the correlation and agreement between these two temperatures in describing thermal changes in menstrual cycles. Methods This prospective study included 193 cycles (170 ovulatory and 23 anovulatory) collected from 57 healthy women. Participants wore a wearable device (Ava Fertility Tracker bracelet 2.0) that continuously measured the wrist skin temperature during sleep. Daily BBT was measured orally and immediately upon waking up using a computerized fertility tracker with a digital thermometer (Lady-Comp). An at-home luteinizing hormone test was used as the reference standard for ovulation. The diagnostic accuracy of using at least one temperature shift detected by the two temperatures in detecting ovulation was evaluated. For ovulatory cycles, repeated measures correlation was used to examine the correlation between the two temperatures, and mixed effect models were used to determine the agreement between the two temperature curves at different menstrual phases. Results Wrist skin temperature was more sensitive than BBT (sensitivity 0.62 vs 0.23; P<.001) and had a higher true-positive rate (54.9% vs 20.2%) for detecting ovulation; however, it also had a higher false-positive rate (8.8% vs 3.6%), resulting in lower specificity (0.26 vs 0.70; P=.002). The probability that ovulation occurred when at least one temperature shift was detected was 86.2% for wrist skin temperature and 84.8% for BBT. Both temperatures had low negative predictive values (8.8% for wrist skin temperature and 10.9% for BBT). Significant positive correlation between the two temperatures was only found in the follicular phase (rmcorr correlation coefficient=0.294; P=.001). Both temperatures increased during the postovulatory phase with a greater increase in the wrist skin temperature (range of increase: 0.50 °C vs 0.20 °C). During the menstrual phase, the wrist skin temperature exhibited a greater and more rapid decrease (from 36.13 °C to 35.80 °C) than BBT (from 36.31 °C to 36.27 °C). During the preovulatory phase, there were minimal changes in both temperatures and small variations in the estimated daily difference between the two temperatures, indicating an agreement between the two curves. Conclusions For women interested in maximizing the chances of pregnancy, wrist skin temperature continuously measured during sleep is more sensitive than BBT for detecting ovulation. The difference in the diagnostic accuracy of these methods was likely attributed to the greater temperature increase in the postovulatory phase and greater temperature decrease during the menstrual phase for the wrist skin temperatures.

Reliability of Non-Contact Infrared Thermometers for Fever Screening Under COVID-19

“…Triple neck temperature detection still had the highest sensitivity of 0.998, whereas the temporal and frontal temperatures had sensitivities of 0.994 and 0.990, respectively. Remarkably, the triple wrist temperature detection sensitivity was only 0.949, which is inconsistent with that in previous reports, 20 , 46 , 47 questioning the accuracy of wrist temperature measurements for COVID-19 fever screening.…”

Novel Technique for Confirmation of the Day of Ovulation and Prediction of Ovulation in Subsequent Cycles Using a Skin-Worn Sensor in a Population With Ovulatory Dysfunction: A Side-by-Side Comparison With Existing Basal Body Temperature Algorithm and Vaginal Core Body Temperature Algorithm

“…3) Although the usefulness of knowing the exact date of ovulation in a prior cycle can be questioned, it is generally accepted that better knowledge of the fertile window provides a higher chance of conception and that the more accurately this is known, the higher the chance of conception (Wilcox et al, 1995;Dunson et al, 2002). 4) With an accuracy of 90% and F score of 0.93 for the ±3 days threshold, SWS appears to be a more accurate method for the confirmation of the fertile window than previously studied methods of oral temperature (Freundl et al, 2003) (accuracy 78%, F score 0.88) and skin temperature (Goodale et al, 2019;Zhu et al, 2021) (F score of 0.78) in determining the fertile window. However, comparison of these results with other studies should be treated with caution, as it is carried out on a distinct user population with a distinct device and algorithm.…”

“…It follows that by applying similar sensor construction and algorithm techniques, other systems could also be made to work as well for the underside of the wrist as well as the arm. Some existing products use the top side of the wrist for temperature measurement (Goodale et al, 2019;Zhu et al, 2021), and the results from this study cannot therefore be used to draw an inference of potential accuracy for those systems.…”

“…The sensors combined with the computing power of mobile devices make the application of algorithmic techniques much easier, both in determining the most representative overnight temperature and in understanding the temperature rise as the cycle progresses. Various publications have attempted to assess the accuracy of oral temperature (Freundl et al, 2003), skin temperature recorded on the top of the wrist (Goodale et al, 2019;Zhu et al, 2021), and vaginal temperature (Papaioannou et al, 2013a;Papaioannou et al, 2013b;Papaioannou et al, 2014;Regidor et al, 2018) for the determination of the date of ovulation by different statistical techniques, comparing the test method variously with ultrasound ovarian follicle measurements (to determine the date of ovulation by estimated date of follicle rupture), urinary luteinizing hormone (LH) results (to determine the date of ovulation as 24-48 h following two positive results), and BBT using the "TOS" rule. Although these comparator methods provide imperfect estimates of the date of ovulation, the results are nonetheless useful with a larger volume of cycles in determining the likelihood that the test method has provided a good understanding of the presence or absence of ovulation, and the day of ovulation.…”

Infrared Thermography in Wound Care, Surgery, and Sports Medicine: A Review

“…Temperature monitoring is a useful tool for many applications ranging from fertility cycle tracking ( Zhu et al, 2021 ) to ulceration prognosis ( Houghton et al, 2013 ). In particular, it could serve as an early warning system in many applications, including the management of open foot ulcers, Charcot foot, and assessment of the risk of re-ulceration.…”