Conventional stimulation IVF
Conventional stimulation IVF is defined as when 150IU or more gonadotrophin daily were administered, including when long term GnRH-a is used for pituitary down-regulation followed by high doses of stimulation(150 – 450 U) with rFSH (Gonal-F® , Ares Serono, Geneva, Switzerland or Puregon® ,NV Organon, Oss, The Netherlands, randomly) or hMG (Meropu® r , Ferring, Milan, Italy), or when GnRH agonist (Cetrotide® injection of 0.25 mg, Merck Biopharma Co., Ltd) is administered in a flare protocol with high doses of stimulation( 150 – 450 U) with rFSH or hMG, or when GnRH antagonist is used with conventional doses of early start of rFSH or hMG . When at least one dominating follicle exceeded a mean diameter of 14–18 mm and serum estradiol was 800-1000pmol/L per follicle, 6,500IU HCG(r-hCG Ovitrelle® , 6500 IU, Merck, Rome, Italy)were given as trigger, and a transvaginal oocyte retrieval followed 36 hours later.
After in vitro fertilization or intracytoplasmic sperm injection according to the husbands’ semen samples, embryo morphology was assessed on the third day after oocyte retrieval. All available embryos were transferred on day 3 after the retrieval. Remaining supernumerary embryos were vitrified, and no more than 2 embryos were transferred in subsequent naturally prepared frozen cycles.
Luteal phase support of progesterone (Duphaston® 10 mg; Abbott BV, Netherlands) or micronized progesterone (Crinone® 8% Wyeth-Ayerst Laboratories, Inc., Philadelphia, PA) or dydrogesterone (Utrogestan® 200 mg, Besins Healthcare) were used for 2 weeks until the determination of pregnancy.