Leptin during assisted reproductive cycles: the effect of ovarian stimulation and of very early pregnancy

Leptin may have a role in human reproduction, The impact of IVF and of very early pregnancy on serum leptin concentrations was studied in 66 infertile patients, of whom 19 became pregnant. Ovarian suppression was accompanied by a fall in leptin concentrations (21 +/- 4%, mean +/- SE; P < 0.01) from the mid-luteal phase, and ovarian stimulation by a rise (76 <plus/minus> 8% ; P < 0.0001) from suppression, The mid-luteal concentration of leptin afte r stimulation was 28 <plus/minus> 7% higher than that during the preceding normal cycle (P < 0.001), Concentrations of leptin and oestradiol were rela ted before treatment, at ovarian suppression and at 8 days after oocyte ret rieval, In addition, the rises in leptin and oestradiol concentrations duri ng stimulation were correlated, but only in those patients who became pregn ant (r = 0.69; P = 0.001). Women with a successful pregnancy had higher con centrations of leptin (18.7 <plus/minus> 4.8 mug/l) at 12 days after embryo transfer than those who had miscarriages (10.0 +/- 1.9 mug/l; P < 0.001), or those failing to become pregnant (11.6 <plus/minus> 1.2 mug/l; P < 0.000 1), We concluded that leptin concentrations are influenced by ovarian funct ion and that the relationship between leptin and oestrogen (but not a singl e leptin concentration), may be an important factor for the outcome of IVF.