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. PARTICIPANT(S): One hundred and seven normally fertile and cycling women. MAIN OUTCOME MEASURE(S): 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.
This multicenter study has produced a database of 7017 menstrual cycles contributed by 881 women. It provides improved knowledge on length and location of the "fertile window" (identified as of up to 12 days duration) and the patterns and level of daily conception probability. The day of ovulation was identified in each cycle from records of basal body temperature and mucus symptoms. By referencing days of intercourse to the surrogate ovulation markers, estimates of daily fecundability were computed either directly or by the Scwartz model, both for single and multiple acts of intercourse in the fertile window. The relationship between coital pattern and fecundability has been explored. Univariate analysis underlines the significant link with fecundability only of the woman's reproductive history.
Four points on the basal body temperatures (BBT) curve have been correlated with the estimated time of ovulation (ETO), as determined by indirect hormonal parameters, in 74 menstrual cycles from 24 subjects. Only 10 of 66 hormonally
Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age, typically characterized by irregular menstrual cycles. Our study found that postpartum menstrual cycles were largely restored in PCOS patients following assisted reproductive technology (ART) therapy. However, this recovery in menstrual cycles was not associated with any specific ART procedures. Using a PCOS mouse model, we demonstrated that elevated progesterone levels during pregnancy were responsible for normalizing estrous cyclicity. Elevated levels of progesterone induce granulosa cell apoptosis and deplete large follicles, which potentially contribute to ovarian function suppression during pregnancy. Mechanistic studies indicated that progesterone decreased follicle-stimulating hormone receptor (FSHR) expression in a GATA binding protein 2 (GATA2)-dependent manner. Interestingly, the capacity of granulosa cells to convert androgens to estrogens significantly increased after progesterone withdrawal, as evidenced by elevated cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) expression in granulosa cells when stimulated with FSH. Additionally, we found that progesterone administration reduced the thickness of the uterine endometrium in PCOS mice. Our findings suggest that sustained high levels of progesterone during pregnancy can enhance ovarian reproductive endocrine capacity and improve endometrial function, thereby facilitating the recovery of postpartum menstrual cycles.
To identify preconception clinical and multi-omics factors associated with conception and early pregnancy loss in women with unexplained recurrent pregnancy loss (URPL). In this prospective cohort study, 149 women with URPL selected from 420 outpatients based on guideline-recommended criteria were enrolled between November 2024 and May 2025 and followed-up for 12 months. Preconception fasting plasma was analyzed for clinical biomarkers, untargeted metabolomics, and data-independent acquisition proteomics. Outcomes included conception, ongoing pregnancy beyond 12 weeks and early pregnancy loss before 12 weeks. Multivariable logistic regression was used to evaluate the associations of clinical and multi-omics factors with reproductive outcomes, adjusting for maternal age, body mass index, number of prior losses, and use of assisted reproductive technology. Of 149 women, 99 conceived (66.4%) during the follow-up. By 12 weeks of gestation, 67 (67.7%) had ongoing pregnancies and 32 (32.3%) experienced early pregnancy loss. Higher testosterone was associated with lower probability of conception (adjusted odds ratio [aOR] 0.50, 95% confidence interval [CI] 0.28-0.89, p = 0.019). Women who conceived showed higher levels of progesterone-related metabolites, including 17-hydroxyprogesterone (fold change, FC = 3.89), pregnanediol 3-O-glucuronide (FC = 2.37), and pregnanetriol 3α-O-β-D-glucuronide (FC = 2.39). Among women who conceived, higher prolactin was associated with higher odds of early pregnancy loss (aOR 1.09, 95% CI 1.01-1.18, p = 0.036), and anti-phosphatidylserine/prothrombin showed a borderline association (aOR 1.07, 95% CI 1.00-1.14, p = 0.052). Early pregnancy loss was characterized by lower bile acid-related metabolites and higher caffeine and methylxanthine metabolites. Proteomic analysis showed enrichment of bile acid biosynthetic process. After adjustment, higher 7α,12α-dihydroxy-3-oxocholest-4-en-27-oic acid was associated with lower odds of early pregnancy loss (aOR 0.64, 95% CI 0.44-0.95, p = 0.025). Higher testosterone was associated with lower odds of conception. Among women who conceived, early pregnancy loss was associated with higher prolactin, borderline higher anti-PS/PT, lower bile acid-related metabolites, and higher caffeine-related metabolites, with 7α,12α-dihydroxy-3-oxocholest-4-en-27-oic acid identified as an exploratory metabolomic candidate. These findings suggest that potential androgen-related biology, prolactin, non-criteria antiphospholipid antibodies, and bile acid metabolism may be associated with reproductive outcomes in URPL, warranting validation in independent cohorts.