Progesterone sustained release vaginal gel

Luteal phase support was applied in all women, commencing on the insemination day. It consisted of 200 mg/d progesterone soft capsules (Utrogestan; Besins, Brussels, Belgium) or 20 mg/d dydrogesterone (Duphaston; Abbott, Hoofddorp, The Netherlands) or 90 mg/d progesterone sustained-release vaginal gel (Merck Serono S.p.A., Darmstadt, Germany) for 14 days. A serum β-hCG assay was performed on the 14th day after insemination to assess whether pregnancy had occurred. If the result was positive, TVS was performed after 14–16 days, and luteal phase support would be maintained until 10 to 12 weeks of gestation.

Female patients were subjected to a standardized ovarian stimulation regimen, with protracted down-regulation with gonadotrophin-releasing hormone agonist (GnRH-a) (Diphereline, lpsen, France), followed by daily use of recombinant follicle-stimulating hormone (Gonal-f, Merck Serono, Germany), which was based on the ovarian response. The ovarian response was monitored by three-dimensional ultrasonography and serum hormone levels, and daily doses of Gonal-f were adjusted for ovarian hyperstimulation. Final maturation of oocytes was induced by injecting recombinant Human Chorionic Gonadotropin (HCG, Merck, Darmstadt, Germany) at doses of 5000 to 10,000 IU when at least 60% of follicular diameters were ≥ 18 mm. Vaginal ultrasound-guided oocyte retrieval was performed after thirty-six hours. Routine IVF or ICSI, according to the sperm quality, was performed after oocyte retrieval. Luteal support was started on the day of oocyte retrieval by injecting 60 mg of progesterone (Xianju, Zhejiang, China) or via the intravaginal administration of 90 mg of a progesterone sustained-release vaginal gel (Merck Serono, Germany).

In this study, all the embryos were vitrified. Frozen embryo transfer (FET) can be performed in the second menstrual cycle or later. Endometrial preparation protocols included the natural cycle, artificial cycle, induced ovulation cycle and downregulation + artificial cycle, which were mainly based on whether the patient’s ovulation was normal or not, and were also combined with the patient’s timing. The natural cycle was mainly used for women with regular menstrual cycles and spontaneous ovulation. Follicular development was monitored by transvaginal ultrasound, luteal-phase support was applied on the day of ovulation with oral dydrogesterone (2 times daily, 10 mg once) (Abbott Co. America) and intravaginal administration of 90 mg of a progesterone sustained-release vaginal gel (Merck Co. Germany), and 1-2 cleavage stage embryos were transferred 3 days later or 1 blastocyst was transferred 5 days later. The artificial/induced ovulation cycle for women with irregular menstrual cycles was done as previously reported (17 (link)). Downregulation + artificial protocols were used for women with endometriosis. GnRH agonist 3.75 mg was applied on the 2nd-3rd day of the menstrual cycle, and 28-30 days later, the endometrium was prepared with the artificial cycle. In women with clinical pregnancy, luteal-phase support was continued at least until 55 days after FET.