Using Circadian Rhythm Patterns of Continuous Core Body Temperature to Improve Fertility and Pregnancy Planning

Abstract

Objective: Review relationships among circadian clocks, core body temperature (CBT), and fertility in women. Methods: Scoping literature review. Results: Circadian clocks are a ubiquitous adaptation to the most predictable environmental events-the daily cycles of light and dark. Core body temperature (CBT) also follows a circadian rhythm. Additionally, CBT is tightly controlled by a combination of neuronal circuits that begin in the hypothalamus and involve many other portions of the brain as well as a wide range of peripheral mechanisms. In women with normal reproductive function, the diurnal temperature pattern for CBT is strongly influenced by the menstrual cycle of reproductive hormones, primarily estradiol and progesterone, which modulate the activity of hypothalamic neural circuits involved in body temperature control, resulting in an infradian CBT rhythm. Conclusions: Analysis of CBT via continuous recording reveals patterns in the interactions of circadian and infradian CBT rhythms capable of accurately predicting the fertility window and hormonal patterns suggesting oligo-ovulation and subfertility. New wearable technologies can facilitate employment of hormone-associated changes in CBT for pregnancy planning and offer clinical insight to infertility and menopause.

Adolescent Development of Biological Rhythms: Estradiol Dependence and Effects of Combined Contraceptives

“…Future research is needed to determine if rhythmic patterns of sex steroid administration more closely mimicking endogenous release, analogous to those implemented in cortisol(67) and closed loop insulin therapy(178), can minimize rhythmic disruption. Conversely, future studies that validate an “updated” symptom-thermal method using signal processing of continuous CBT data may provide feasible, non-disruptive alternatives for contraception(106,139,179–181). Contraceptive administration to adolescent girls is on the rise(74), and there are a paucity of data on the impact of chronic hormonal perturbation on endogenous rhythmicity, or if such disruptions during the sensitive window of adolescence have lasting effects(93,94,101,182,183).…”

“…In contrast, CBT exhibits clear URs, CRs, and ORs that reflect underlying hormonal changes(6,61,104), including ultradian rhythmic CBT patterns that mirror LH(21, 105) and estradiol(21) prior to ovulation. Likewise, CBT is a reliable phase marker for circadian rhythmicity(106, 107). Hormonal alterations across the ovulatory cycle directly influence CBT, with E2 decreasing temperatures prior to ovulation, and E2 with progesterone increasing temperature following ovulation(8, 106).…”

“…Likewise, CBT is a reliable phase marker for circadian rhythmicity(106, 107). Hormonal alterations across the ovulatory cycle directly influence CBT, with E2 decreasing temperatures prior to ovulation, and E2 with progesterone increasing temperature following ovulation(8, 106). As a result, we hypothesized that insight into changes in the temporal structure of underlying physiology across adolescence can be garnered via assessment of continuous CBT levels and rhythms.…”

Development of Ingestible Thermometer With Built-in Coil Antenna Charged by Gastric Acid Battery and Demonstration of Long-Time in Vivo Telemetry

“…One reason for this prediction is that core body temperature and its temporal patterns, especially during sleep, are fundamental vital signs, and thus can be used for various purposes. Hence, their monitoring and logging can potentially help to detect various diseases earlier or more accurately, such as menstrual disorders [20], polycystic-ovary syndrome [21], depression [22], infection [23], and a specific sleep disorder [24], [25]. In addition, the core body-temperature rhythm is a strong indicator of the circadian rhythm (inner-body clock).…”

Development of Ingestible Thermometer with Built-in Coil Antenna Charged by Gastric Acid Battery and Demonstration of Long-Time in vivo Telemetry

“…monitoring and logging can potentially help to detect various diseases earlier or more accurately, such as menstrual disorders [18], polycystic-ovary syndrome [19], depression [20], infection [21], and a specific sleep disorder [22][23]. In addition, the core body-temperature rhythm is a strong indicator of the circadian rhythm (inner-body clock).…”