Corticosteroids, androgens, progestogens and oestrogens in the endometrial microenvironment, and their association with endometrial progression and function.

RESEARCH QUESTION: How does the intracrine action of progestagens, oestrogens, androgens and corticosteroids affect endometrial tissue progression and function?

DESIGN

In this prospective observational study, 76 patients (<50 years old, no uterine pathologies and at least one failed IVF cycle) undergoing endometrial biopsy collection for endometrial evaluation between 2018 and 2021 were included. The concentrations of 11 steroid metabolites (cortisone, cortisol, progesterone, oestrone, 2-methoxyestrone, oestradiol, oestriol, testosterone, androstenedione, 17α-hydroxyprogesterone and 17-hydroxypregnenolone) were measured by ultra-performance liquid chromatography-tandem mass spectrometry in the endometrial tissue samples collected during the mid-secretory phase. Endometrial dating and reproductive outcomes (relative to the next good-quality fresh or frozen embryo transfer after the biopsy) were analysed in relation to endometrial steroid concentrations using Barnard's test; correlations between metabolite concentrations were measured by Pearson's correlation co-efficient.

RESULTS

Endometrial cortisol concentrations increased with age, whereas oestrone and 17α-hydroxyprogesterone concentrations had inverse relationships with body mass index (all P < 0.05). No statistically significant differences were found in age or body mass index related to endometrial progression and reproductive outcomes. Low endometrial progesterone (<40.07 μg/g), along with high endometrial cortisol (>2.18 ng/g) and testosterone concentrations (≥0.52 ng/g), were mainly associated with out-of-phase endometria. Although low oestrone (<21.27 ng/g) and high androstenedione endometrial concentrations (≥1.35 ng/g) impaired reproductive success, low oestradiol (<1.15 ng/g) endometrial concentrations favoured conception (all P < 0.05).

CONCLUSIONS

In addition to progesterone and oestrogens, other steroid hormones are involved in intracrine signalling, and are probably necessary for acquiring adequate endometrial competence and supporting conception.