Vaginal Progesterone Improves Clinical Outcomes of RIF Patients

According to the enrollment and exclusion criteria, the patients were enrolled, and the subjects were randomly divided into two groups by computer randomization. Group A was the vaginal progesterone added group (test group). Group B was the regular FET group (control group).

• progesterone vaginal sustained-release gel (Drug): 90 mg progesterone vaginal sustained-release gel is added daily during endometrial transformation and luteal support

Primary outcomes

• Embryo implantation rate [45 days after embryo transfer]: The proportion of the number of implanted embryos to the total number of transferred embryos is the embryo implantation rate.

Secondary outcomes

• Clinical pregnancy rate [45 days after embryo transfer]: Clinical pregnancy is defined as the presence of gestational sac observed by ultrasound. The proportion of clinical pregnancy cycles to total FET cycles is the clinical pregnancy rate.
• Early pregnancy loss rate [12 weeks after embryo transfer]: The early pregnancy loss rate refers to the proportion of patients with pregnancy loss before 12 weeks of gestation in the total clinical pregnancy patients.
• Persistent pregnancy rate [20 weeks after embryo transfer]: The ratio of the number of pregnancies lasting to 20 weeks to the number of transplant cycles.
• Live birth rate [40 weeks after embryo transfer]: The ratio of the number of live fetal delivery cycles to the number of transplantation cycles after 28 weeks of pregnancy.

Sex: Female, ages: 20 Years to 40 Years

Inclusion Criteria:

1. Aged between 20 and 40 years old;
2. BMI: 18-28 kg/m2；
3. Consistent with the diagnosis of repeated implantation failure of unknown reasons, the previous embryo transfer situation meets one of the following:

   Total embryos transferred ≥ 4 high-quality cleavage-stage embryos; ≥ 2 blastocysts; ≥ 2 high quality cleavage-stage embryos +≥ 1 blastocysts;
4. At least 1 high-quality embryo remained for embryo transfer;
5. Volunteer to participate in the study and sign the informed consent form.

Exclusion Criteria:

1. Patients with recurrent pregnancy loss (≥ 2 biochemical pregnancies or ≥ 2 spontaneous abortions);
2. Adverse pregnancy history (stillbirth, fetal malformation, etc.);
3. Severe paternal factors: need for TESA or PESA;
4. PGT;
5. Failure of embryo implantation due to any definite reason, including but not limited to: endometrial adhesion (moderate to severe), thin endometrium (<7 mm before transformation), endometritis, endometriosis (medium or severe), adenomyosis, untreated hydrosalpinx, hysteromyoma (submucosal fibroids, non submucosal fibroids > 4.0 cm and/or endometrial compression), reproductive malformation, serious immune disease, serious coagulation function abnormality;
6. Chromosome abnormality of either spouse;
7. Those with contraindications to pregnancy or assisted reproductive technology.