Hormonal and metabolic responses across phases of combined oral contraceptive use and menstrual cycle in young elite female athletes.

PURPOSE: Despite the significant number of female athletes using combined oral contraceptives (COCs), there is scant literature on their hormonal and metabolic effects across different phases.

METHODS

In order to contribute to a wider knowledge of COC-action mechanisms involved in athletes' performance and health, we therefore examined the effects of low-dose monophasic COC (ethinylestradiol/levonorgestrel) intake on sex hormones (estradiol, progesterone, sex hormone binding protein (SHBG)) as well as on a large number of pituitary (LH, TSH, prolactin) and peripheral (triiodothyronine, cortisol, DHEA, DHEA-S, aldosterone, osteocalcin, 25(OH)D) basal hormone levels in nine young elite female athletes, across COC administration (first and second half of active hormone intake, washout phases), compared to eleven female athletes without hormonal contraception across their normal menstrual cycle (NMC, i.e., early follicular, end follicular/peri-ovulatory, mid-luteal phases).

RESULTS

COC vs. NMC increased SHBG (p < 0.01), TSH, cortisol and 25(OH)D (p < 0.05), and decreased DHEA and DHEA-S (p < 0.05) concentrations. Across COC and NMC phases, higher estradiol and aldosterone concentrations (p < 0.05) were observed during the washout and mid-luteal phases, respectively.

CONCLUSION

In highly trained female athletes, COC vs. NMC induced several hormonal alterations, irrespective of the phases, leading to potential ergogenic and clinical repercussions that merit clarification. In NMC athletes, the impact of endogenous sex hormone fluctuations on the parameters studied appeared limited, perhaps mitigated by intense physical training, with only aldosterone change. Given the high prevalence of vitamin D insufficiency, it seems warranted to monitor this parameter, not yet routinely considered in female athletes, taking into account COC intake.

TRIAL REGISTRATION: ID-RCB:2020-A02965-34, France.