الفهرس 
1-IntroductionOnly 14 pages are availabe for public view
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Abstract
Improving ICSI outcome has been a much desired goal in the field of ART. Several interventions have been proposed and evaluated in different centers giving different success rates (Assisted Reproductive Technology Success Rates , National Summary and Fertility Clinic Reports 2006). Historically, little attention has been paid to the embryo transfer procedure. This fact is reflected by the dearth of scientific publications regarding embryo transfer compared with other aspects of IVF (e.g. ovarian stimulation), and also the reluctance of physicians to modify their own personal habits to encompass a more evidence-based approach.
These facts stimulated me to do this systematic review to reach a conclusion aiming at optimizing the procedures of embryo transfer.
To do this an electronic search of the following data bases and electronic sites was done (Cochrane database, Pubmed, Medline and Science direct). This search yielded 263 results which were identified as potentially relevant. Only 87 of them met the inclusion criteria of the study and were considered eligible. They included 14 studies for the timing of embryo transfer, 16 studies for the number of embryos to transfer, and 57 studies for the technique of transfer.
Data were collected from these studies, summarized and tabulated clearly. This was followed by summation of the evidences of the studies on each topic and conclusions were presented with the power of evidence justifying each.
The followings are the final conclusions obtained from the systematic review:
1. In patients with good prognosis, with high number of 8-cells embryo on day 3, blastocyst embryo transfer is favoured, and in those patients single embryo transfer is applicable and should be considered. (evidence level : Ia ).
2. Although there’s significant increase in the clinical pregnancy rate with embryo transfer on day 3 more than day 2, there is no sufficient good quality evidence to suggest improved live birth rate with day 3 embryo transfer. This is due to increase in the miscarriage rate in ICSI cycles on day 3 embryo transfer.( evidence level : Ia ).
3. Contradictory data were found as regards the benefits of day 2 versus day 3 embryo transfer in case of poor ovarian response and larger studies and meta-analysis are needed to reach more reliable results. (evidence level:Ib).
4. In women with 7 or less metaphase 2 oocytes: a- day 3 embryo transfer is better than day 2 embryo transfer in case of maternal age 36 years old or less. b- there is no significant difference between day 2 and day 3 embryo transfer in case of maternal age more than 36 years old. (evidence level:IIb).
5. For thawed frozen embryo transfer: although clinical pregnancy rate is similar for day 3 and day 5 embryo transfer, the ongoing pregnancy rate is significantly higher with day 3 embryo transfer. (evidence level:Ib).
6. Despite similar implantation rates, fresh double-embryo transfer has a 1.64 to 2.60 times greater ongoing pregnancy rate and 1.44 to 2.42 times greater live birth rate than single-embryo transfer in a population suitable for ART treatment. (evidence level: Ia).
7. In a single fresh IVF cycle, single-embryo transfer is associated with a lower live birth rate than double-embryo transfer. However there is no significant difference in cummulative live birth rate following single-embryo transfer followed by single frozen embryo transfer and the live birth rate following a single cycle of double-embryo transfer. Multiple pregnancy rates are lowered following SET compared with other transfer policies. (evidence level: Ia).
8. Elective single-embryo transfer in young patients may have a favourable outcome compared with double-embryo transfer. This favourable outcome of elective single-embryo transfer is not limited to fresh but frozen embryos. These patients are candidates for single-embryo transfer and should be informed about the possible morbidities associated with multiple pregnancies and births. (evidence level:Ib).
9. As regards cleavage stage embryo transfer : for patients younger than 38 years old no more than two embryos should be transferred. For patients who are 38 or 39 years old no more than 3 or 4 embryos should be transferred respectively, whereas upto five embryo transfers could be performed for the patients who are 40 years old and older. (evidence level: IIb).
10. As regards blastocyst embryo transfer : for patients younger than 40 years old no more than two embryos should be transferred. For patients who are 40 years and older no more than 3 embryos should be transferred with increased risk of multiple birth in comparison to double embryo transfer except for patients who are 40 years old. (evidence level: IIb).
11. As regards frozen embryo transfer :Transfer of two instead of three frozen embryos in patients <35 years old decreases multiple pregnancy rate without compromising pregnancy rate or live birth rate. In the age group 35–39 years, transferring two instead of three embryos doesn’t decrease pregnancy rate or live birth rate, and has no effect on the risk of high-order multiples. (evidence level: IIb).
12. Single frozen blastocyst embryo transfer may be a viable option in young age patients without compromising overall pregnancy rate in comparison to multiple frozen blastocyst embryo transfer. (evidence level: IIb).
13. Soft embryo transfer catheters should be the gold standard in the practice of embryo transfer. (evidence level: Ia).
14. There’s increased catheter insertion failure rate and increased incidence of traumatic events following embryo transfer using soft catheter. However this doesn’t affect the overall pregnancy outcome. (evidence level: Ia).
15. There’s no statistically significant difference between different soft embryo transfer catheters as regards pregnancy rates. (evidence level: Ia).
16. Echogenic soft embryo transfer catheters are associated with marked ease of transfer and simplification of the procedure but no significant difference as regards pregnancy rates except for increased twin rates with echogenic catheters. (evidence level: Ib).
17. When comparing different firm embryo transfer catheters, Tom Cat and Tefcat yielded better results than the Tight Difficult Transfer (TDT) catheters but comparable to each other. (evidence level :Ia).
18. Some studies suggest that the difference in the outcome of different embryo transfer catheters are operator dependent, yet more well designed studies are needed to give definite conclusion. (evidence level: Ib).
19. Filling the bladder prior to embryo transfer is associated with significantly better clinical pregnancy rate and should be done as a routine when doing embryo transfer. (evidence level: Ia).
20. The use of a stylet during the procedure of embryo transfer doesn’t affect the pregnancy rates. (evidence level: IIb).
21. The presence of mucus (and/or) blood (either macroscopically or microscopically) on the embryo transfer catheter doesn’t have a significant effect on the pregnancy outcome. (evidence level: IIa).
22. Contamination of the embryo transfer catheter with mucus (and/or) blood was associated with a significant increase of number of retained embryos with no detrimental effect on the clinical pregnancy rate when the embryos were retransferred. (evidence level: IIb).
23. Cervical dilatation prior to embryo transfer is not beneficial in cases of failed dummy embryo transfer and it should not be recommended as the optimum choice for women with difficulty during embryo transfer and other options should be investigated. (evidence level: IIa).
24. Using ultrasonographic guidance during embryo transfer improves overall pregnancy and implantation rates in comparison to the clinical touch method . (evidence level: Ia). However, this difference is much attenuated with experienced hands. (evidence level: Ib).
25. Using transvaginal ultrasonography for guiding embryo transfer gives similar results to the use of transabdominal ultrasonography. (evidence level: Ib).
26. The use of ultrasonographic measurement of the uterine length prior to embryo transfer could be an alternative precise and a traumatic technique of embryo transfer. (evidence level: Ib).
27. 4D ultrasonographic guided embryo transfer gives significantly higher pregnancy rates than 2D ultrasonography but still the latter has a considerably high success rate. (evidence level: IIa).
28. The afterload technique is refinement of the standard embryo transfer technique and significantly increase the clinical pregnancy rate by facilitating the embryo transfer. (evidence level: IIa).
29. The afterload method is simpler to teach than the direct insertion method and it negates the difference between experienced and inexperienced embryo transfer performers. (evidence level: IIb).
30. Although studies show that embryo deposition at a distance about 20mm away from the fundus is better than 10mm, the evidence is limited by the heterogeneity of these studies and more well designed studies are needed to reach a definite conclusion. (evidence level: Ia). However, another evidence, albeit of a lower power, indicates that deposition distance should not be less than 0.75 cm and no more than 20 mm. (evidence level: IIa).
31. passing the embryo transfer catheter guide beyond the internal os during the embryo deposition procedure significantly reduces implantation and pregnancy rates and should be avoided during the embryo transfer procedure. (evidence level: IIb).
32. Enrichment of embryo transfer medium with hyaluronan significantly improves clinical pregnancy and implantation rates for both day 3 and day 5 transfer especially in patients older than 35 years, patients with poor quality embryos and patients with history of previous implantation failures. (evidence level: Ib).
33. Using Embryo glue transfer medium significantly increases the Live birth and triplet delivery rates. It also improves clinical pregnancy and implantation rates in cases of tubal factor infertility and implantation rate only in cases of previous implantation failures. (evidence level: Ib).
34. patients with repeated I.V.F. failures would benefit from intra-uterine administration of autologous peripheral blood mononuclear cells (PBMC) prior to embryo transfer in terms of improved clinical pregnancy, implantation and live birth rates. (evidence level: Ib).
35. Contradictory results existed regarding injection of the embryo culture medium intrauterine prior to embryo transfer, ranging from a significant increase in success rate to no effect at all . (evidence level: Ib).
36. Removal of cervical mucus prior to embryo transfer significantly improves clinical pregnancy rate. However if cervical mucus was left in place the procedure was much easier. (evidence level: Ib).
37. No definite conclusion about the significance of Acupuncture on the day of embryo transfer could be reached due to the heterogeneity and differences in the methodology of available studies. (evidence level: Ib).
38. The presence of vaginal–cervical microbial contamination by Entrobacteriaceae and Staphylococcus at the time of embryo transfer is associated with significantly decreased pregnancy rates. (evidence level: IIa).
39. Although Co-amoxiclav reduces embryo transfer catheter bacterial contamination, this is not translated into better clinically relevant outcomes (evidence level: Ib). Further well designed studies are needed to evaluate the routine use of antibiotics at embryo transfer.
40. No definite conclusion could be reached regarding the use of 17-HPC before ET due to lack of sufficient number of studies.
41. No definite conclusion could be reached regarding the administration of piroxicam before embryo transfer in patients receiving adequate doses of progesterone for luteal phase supplementation after IVF or ICSI due to lack of sufficient number of studies.
42. The use of hypnosis during ET may significantly improve the IVF/ET cycle outcome in terms of increased implantation and clinical pregnancy rates.(evidence level: IIb). However more studies are needed to confirm these results and to standardize the procedure.
43. The oral use of low-dose aspirin therapy, when started concomitantly with controlled ovarian stimulation, did not affect UtA vascular impedance on the day of embryo transfer. However, the incidence of non-optimal uterine haemodynamics was significantly lower.(evidence level: Ib). However more studies are needed to reach a definite conclusion.
44. The use of oxytocin antagonist drug Atosiban increases the Implantation rate and pregnancy rate and decreases the miscarriage rate and may constitute a new treatment opportunity In embryo-transfer procedures. (evidence level: Ib). However more studies are needed to reach a definite conclusion.
45. There is insufficient evidence to suggest that the fluid-only method is superior to the use of air brackets during embryo loading. There is a need for well-designed and powered randomized trials to determine any possible benefit to either method. (evidence level: Ia).
46. Available evidence does not support the presence of any beneficial effect of bed rest following embryo transfer on the outcome of IVF/ICSI procedure. (evidence level: Ib).
47. The timing of a mock embryo transfer does not affect in vitro fertilization implantation or pregnancy rates. (evidence level: IIa). However more studies are needed to reach a definite conclusion.
48. The timing of embryo transfer catheter removal after deposition of embryos does not seem to affect pregnancy rates in IVF cycles. yet patients in whom the first ART cycle was unsuccessful after immediate transfer may benefit from delayed transfer catheter removal in the subsequent cycle. (evidence level: IIb). However more studies are needed to reach a definite conclusion.