The impact of polycystic ovary syndrome and body mass index on the absorption of recombinant human follicle stimulating hormone

Purpose Women with polycystic ovary syndrome (PCOS) have an increased ovarian responsiveness to exogenous recombinant follicle stimulating hormone (rFSH) but also have high rates of obesity, which is known to affect serum FSH concentrations following exogenous injection. The purpose of this study was to compare rFSH absorption and ovarian response between lean and overweight/obese PCOS subjects and normo-ovulatory controls. Methods Fourteen women with PCOS aged 18–42 years old with a BMI of 18.5–24.9 kg/m 2 (normal) or 25.0–40.0 kg/m 2 (overweight/obese) and eleven normo-ovulatory controls matched by age and BMI were included. After downregulation with oral contraceptives, participants were administered a single subcutaneous injection of 225 IU rFSH and underwent serial blood draws over 72 h. Results Lean PCOS subjects exhibited a significantly higher area under the curve (AUC) of baseline-corrected serum FSH over 72 h when compared with overweight/obese PCOS subjects (183.3 vs 139.8 IU*h/L, p = 0.0002), and lean, normo-ovulatory women had a significantly higher AUC FSH when compared with overweight/obese, normo-ovulatory women (193.3 vs 93.8 IU*h/L, p < 0.0001). Within overweight/obese subjects, those with PCOS had a significantly higher AUC FSH compared with normo-ovulatory controls ( p = 0.0002). Lean PCOS subjects similarly had the highest AUC of baseline-corrected estradiol (6095 pg h/mL), compared with lean normo-ovulatory subjects (1931 pg h/mL, p < 0.0001) and overweight/obese PCOS subjects (2337 pg h/mL, p < 0.0001). Conclusion Lean PCOS subjects exhibited significantly higher baseline-corrected FSH and estradiol levels following rFSH injection compared with overweight/obese PCOS subjects with similar ovarian reserve markers. Amongst overweight/obese subjects, those with PCOS had significantly higher FSH and E2 levels when compared with normo-ovulatory controls.