Comparison Of Clomiphene And Letrozole For Superovulation In Patients With Unexplained Infertility Undergoing Intrauterine Insemination:A Systematic Review And Meta-analysis

Background: With the medical advancement some studies put forward that letrozole,a specific aromatase inhibitor with the function of reducing oestrogen synthesis,has recently been applied as a potentially better alternative compared with CC,owing to that it has a superior efficacy as compared with clomiphene citrate in patients of unexplained infertility undergoing IUI.However,there is no one study can clear and definite whether LE can replace the CC as first line drug.Objective : Our objective is to compare the letrozole(LE)with clomiphene citrate(CC)in the induction of ovulation in patients with unexplained infertility intrauterine insemination(IUI).Method: Searching databases consist of all kinds of searching tools,such as Medline,The Cochrane Library,Embase,PubMed,etc.All the include studies should meet our demand of this meta-analysis: 1.Studies are comparison between letrozole and clomiphene forsuperovulation in patients with unexplained infertility undergoing intrauterine insemination;2.the result include one of outcomes at least or more;3.maybe in some literature they doesn’t use letrozole but the meaning is as same as it,we also adopt them;4.the patients must be at least one side of the unobstructed fallopian tube confirmed by hysterosalpingography(HSG)or laparoscopy;5.uterus is normal that is confirmed by laparoscopy,hysteroscopy,ultrasound,etc.6.semen detection is normal or mildly abnormal that is based on WHO Standard(1999).In all interest outcomes below we take the full advantage of RevMan5 to assess,the main measure is risk ratio(RR)with95%confidence.Result: Based on the current meta-analysis,we rigorously consider that LE has a likelihood to improve dominant follicles(MD=-0.56,I2=100%,P= 0.04;MD=-0.39,I2= 73%,P= 0.0003,respectively)and reduces the miscarriage rate(RR= 0.61,I2= 0%,P= 0.03).There is no significant differences between the two groups in The total rate of pregnancy,Pregnancy rate per cycle,Multiple pregnancy and Endometrial thickness.(RR= 1.06,I2= 11%,P= 0.38;RR= 1.09,I2= 7%,P= 0.32;RR= 0.79,I2=0%,P= 0.46;respectively)Conclusion: Combined with the results of current systematic review and meta-analysis through subgroup analysis and sensitivity analysis,we can be cautious: in general,compared with CC,LE is an effective treatmentin the IUI cycle,has a likelihood to improve dominant follicles and reduces the miscarriage rate.