Recombinant hcg

Pituitary down-regulation was carried out by a follicular phase long-acting GnRH-agonist long protocol. Before ovarian stimulation, all patients received a long-acting GnRH-a (Triptorelin acetate) at a dose of 3.75mg intramuscularly on the day 2-3 of menstruation. After 28 days, ovarian stimulation was initiated if FSH, LH and E2 levels, follicle diameter, and number met the downregulation criteria according to ultrasound and sex hormone examination. The initial dosage of gonadotropin (recombinant FSH, Merck Serono) was 75-300 IU/d as per basal hormone levels, BMI, antral follicle counts and age. The dosage could be adjusted after monitoring follicle growth and endometrial thickness with transvaginal ultrasound and determining serum E2 levels. When the most prominent two follicles reached 17 mm, 10000 IU recombinant-hCG (Serono, Switzerland) was administered intramuscularly for triggering oocyte maturation. We retrieved oocytes approximately 35-37h following triggering by transvaginal ultrasound aspiration, followed by IVF/ICSI as previously described (24 (link), 25 (link)).

In addition to natural cycles without ovarian stimulation, women may also undergo ovarian stimulation to induce ovulation, including clomiphene citrate, letrozole, gonadotrophin (human menopausal gonadotropin (HMG), urofollitropin (Zhuhai Livzon, Zhuhai, China) or recombinant follicle-stimulating hormone (rFSH, Gonal-F, Merck Serono S.p.A., Darmstadt, Germany)) from day 3 to 5 of the menstrual cycle for a variable duration depending on the follicle diameter. Follicles were monitored with the use of transvaginal sonography (TVS) by gynecologists in our department. In both natural and ovary-stimulated cycles, we monitored the follicle from day 10 to 12 of the menstrual cycle and then repeated every 2 or 3 days based on the follicle diameters. Women were advised to cancel a cycle if three or more dominant follicles were present. We performed ovulation triggering with the use of the intramuscular injection of 4000–10,000 IU urinary human chorionic gonadotrophin (hCG) (Zhuhai Livzon, Zhuhai, China) or 0.25 mg recombinant hCG (Merck Serono S.p.A., Darmstadt, Germany) when at least one dominant follicle diameter was assessed to be ≥18 mm. Insemination was performed 36–38 h after triggering.

Ultra-long GnRH agonist protocol has been described previously (7 (link)). Patients received a depot injection of triptorelin acetate (3.75mg; Ferring Pharmaceuticals, Kiel, Germany) 28~30 days before ovarian stimulation on 2~4 days of menstrual cycle and COS started 28~35 days after the last injection. When at least three dominant follicles reached the diameter of 18~20mm, recombinant hCG (250ug; Merck Serono, Coinsins, Switzerland) was injection intramuscularly. The oocytes aspiration was performed 36.5~37.5 hours after trigger.