Reproductive Endocrinology · Ovarian Hormones

Descriptive analysis of the relationship between progesterone and basal body temperature across the menstrual cycle

Écochard R, Leiva R, Bouchard T, Boehringer H, Iwaz J, Plotton I

Published February 2022 Steroids
DOI 10.1016/j.steroids.2022.108964 PMID 35065994

RRM Academy Synopsis

Basal body temperature tracks progesterone only at lower levels

An observational study of 107 healthy women with regular cycles tracked daily temperature and a urine progesterone marker. It covered 283 cycles timed by ultrasound. Temperature tracked progesterone at low levels and stopped tracking it at high levels. The link was medium (r = 0.53).

Key Findings

  • Ultrasound timed ovulation in 283 cycles of 102 women. Temperature and the progesterone marker could be compared over 7,279 days.
  • On the first day of menses, the progesterone marker fell in nearly 90% of cycles and temperature fell in nearly 80%, compared with the end of the previous cycle.
  • Between the second and third day after menses, small but significant decreases appeared in the marker in 76% of cycles and in temperature in 48%.
  • Between the third and second day before ovulation, the progesterone marker began to rise in 56% of cycles and temperature in 41%.
  • The temperature shift rule for the start of the post-ovulatory phase was accurate in 94.7% of 283 cycles. The other 15 cycles (5.3%) had a smaller post-ovulatory rise.

Interpretation

The study is observational and descriptive. The results show how two measures move together and cannot show that one causes the other. The women were normally fertile with regular cycles. The authors excluded polycystic ovary syndrome, recent hormonal contraception and recent infertility treatment, so findings may differ in other groups. The data date from 1996 to 1997. The authors add that urine dilution can still affect the marker, and that illness, night-time breastfeeding and thyroid disorders can alter temperature.

RRM Context

Charting temperature is a core skill in fertility awareness methods. Here ultrasound gave the day of ovulation. Progesterone began to rise a few days before it. The authors recall earlier findings that temperature confirms ovulation after the fact and does not predict it. Progesterone climbs most after ovulation, so a progesterone-centered view is an ovulation-centered view.

Abstract

Objective

Describe the relationship between basal body temperature (BBT) and pregnanediol-3 alpha-glucuronide (PDG, the urine metabolite of progesterone) across the menstrual cycle.

Design

Observational study.

Setting

Study carried out from 1996 to 1997 in eight European family planning clinics.

Participants

One hundred and seven normally fertile and cycling women.

Main Outcome Measures

BBT and PDG level on each day of 283 cycles and ultrasound determination of the day of ovulation.

Result

(s): In comparison with previous end-of-cycle levels, decreases in PDG and BBT on the first day of menses were seen in nearly 90% and 80% of cycles, respectively. In a non-negligible percentage of cycles, luteolysis would continue during menses: between the second and the third day after menses, small but significant decreases in PDG and BBT were seen in 76% and 48% of cycles, respectively. During the peri-ovulatory phase, between the third and the second day before ovulation, PDG and BBT began to rise in 56% and 41% of cycles, respectively. There was a medium degree of correlation between PDG levels and BBT (r = 0.53; 7,279 days with available measurements). The relationship between PDG levels and BBT was linear at low PDG levels but BBT increased no longer when PDG levels continued to rise above a threshold of nearly 10 mcg/mg Cr.

Conclusion

(s): PDG and BBT had parallel increases at low PDG rates but diverged at higher rates.

Topics

By this author

Related research

Reproductive Endocrinology › Ovarian Hormones › Progesterone · Menstrual Cycle › Cycle Biomarkers › Basal Body Temperature · Fertility Awareness › Biomarkers › Basal Body Temperature
René Écochard, René Leiva, Thomas Bouchard, Hans Boehringer, Jean Iwaz, Ingrid Plotton
R Écochard, R Leiva, Tom Bouchard, T Bouchard, H Boehringer, J Iwaz, I Plotton
PMID 35065994 35065994 DOI 10.1016/j.steroids.2022.108964 10.1016/j.steroids.2022.108964 Écochard et al. 2022, Écochard 2022