Study On The Clinical Pregnancy Outcome Of Letrozole Combination With PPOS In IVF-ET

Background:Kuang et al.proposed a new ovulation promoting protocol progestin primed ovarian stimulation in 2015,which is an effective protocol to suppress early LH surge with human menopausal gonadotropin and medroxyprogesterone acetate before the estrogen rising,reducing cycle cancellation rate.It is an effective protocol and widely used in clinical.The results of the previous study provided that PPOS can obtain satisfying pregnancy outcomes in patients with diminished ovarian reserve,aged patients,poor ovarian response.We found that some patients who deeply suppress early LH surge in PPOS,difference of diameter of follicle in actual clinical application and so on.In order to further solve the problems in PPOS,exploring the clinical effect of letrozole combined with PPOS.Objective:To investigate the clinical effect of letrozole combined with progestin primed ovarian stimulation under in vitro fertilization/intracytoplasmic sperm injection-embryo transfer.Methods:Total of 669 cycles of PPOS from different protocol were divided into two groups in January to December 2017,women in study group using letrozole in PPOS（n=329）and control group not using PPOS（n=340）.The general condition,embryo quality and pregnancy outcome of the two groups of patients were compared.Results:1.No significant differences were found between study group and control group in age,infertility years,BMI,AFC,AMH,basal follicle stimulating hormone,basal luteinizing hormone,basal estrogen,basal progesterone.2.Significant differences were found between study group and control group in the level of LH,E₂,P in trigger day,compared with control group,women in study group achieved significantly higher level of LH and P in trigger day,lower level of E₂in trigger day.Significant differences were found between study group and control group in level of FSH the day after trigger,level of LH,E₂and P the day after trigger,compared with control group,women in study group achieved significantly higher level of FSH,LH,P the day after trigger,lower level of E₂the day after trigger.Significant differences were found between study group and control group in the total dose of gonadotropin,the day of gonadotropin,the total dose of medroxyprogesterone acetate,compared with control group,women in study group achieved significantly lower the total dose of gonadotropin,the day of gonadotropin and the total dose of MPA.3.No significant differences were found between study group and control group in number of eggs obtained,number of mature eggs,available embryos.significant differences were found between study group and control group in better quality embryo,compared with control group,women in study group achieved significantly better quality embryo.4.No significant differences were found between study group and control group in the level of estroge,endometrial thickness before transfer and number of transplanted embryos,implantation rate,biochemical pregnancy rate,clinical pregnancy rate,pregnancy loss rate,ectopic pregnancy rate,live birth rate and multiple birth rate.compared with control group,women in study group achieved significantly higher implantation rate（27.55%vs 26.03%）,higher clinical pregnancy rate（47.72%vs 43.82%）and higher live birth rate（35.87%vs 33.53%）.Conclusion:In the case of reducing dosage of gonadotropin and MPA,shorten the day of stimulating,The combination of letrozole and progestin primed ovarian stimulation can achieve the pregnancy outcome as good as PPOS.