Serum leptin concentration duringin vitrofertilization treatment with controlled ovarian hyperstimulation: Serum leptin concentration decreases in the early luteal phase in pregnancy

To investigate the change pattern of leptin duringin vitro fertilization and embryo transfer (IVF-ET) treatment with controlled ovarian hyperstimulation (COH) and at the stages of very early pregnancy. The serum leptin concentration was investigated in 65 patients treated with assisted reproductive technology (ART) in five different periods (ART-1: on the first day of ovarian stimulation with follicle-stimulating hormone; ART-2: at human chorionic gonadotropin administration before oocyte retrieval; ART-3: 7 days after oocyte retrieval; ART-4: 14 days after oocyte retrieval and ART-5: 21 days after oocyte retrieval). The leptin concentration showed significant lower values in the pregnancy group than the non-pregnancy group at ART-3 and ART-4 (P < 0.05). In the pregnancy group, leptin concentration increased from ART-1 (13.5 ±8.2 ng/mL) to ART-2 (23.0 ±15.1 ng/mL) (P < 0.001). The values significantly decrease at 7 days after oocyte retrieval, from ART-2 to ART-3 (18.1 ± 12.0 ng/mL) (P < 0.01), and then showed no remarkable change until 21 days after oocyte retrieval. In the non-pregnancy groups, leptin concentration increased from ART-1 (17.3 ± 11.5 ng/mL) to ART-2 (25.7 ± 12.1 ng/mL) (P < 0.0001). There was no remarkable change in leptin concentration until 14 days after oocyte retrieval, followed by a significant decrease in leptin concentration at ART-4 (21.9 ± 11.9 ng/mL) to ART-5 (18.1 ± 11.8 ng/mL) (P < 0.05). The serum leptin concentration increases during COH in the pregnancy and non-pregnacy groups. In the pregnancy group, leptin concentration showed a fall of leptin values at early luteal phase. These findings might be useful to elucidate the role of leptin in the IVF-ET patients.