A Randomized Single-blind Comparison of Two Embryo Transfer Catheters in Patients Undergoing in Vitro Fertilization and Embryo Transfer

In-vitro fertilization (IVF) treatment involves development of multiple follicles following ovarian stimulation, oocyte retrieval and embryo transfer (ET). Despite recent advances in ovarian stimulation, the method of assisted fertilization and improved culture conditions, the implantation potential of embryos remains around 20-25% for a long time.

ET is the final and most crucial step of IVF treatment and pregnancy rates after ET may be affected by various factors. In a Cochrane meta-analysis (Derks et al., 2009), no evidence of a benefit was found for performing ET with a full bladder, the removal of cervical mucus, and flushing the endocervical canal or the endometrial cavity. No data were found on changing the woman's position, the use of a tenaculum, the performance of a dummy transfer, and embryo afterloading. Other meta-analyses demonstrate that the use of soft ET catheters (Buckett, 2008) and transabdominal ultrasound guidance (Brown et al., 2010) lead to a higher chance of clinical pregnancy when compared with the use of stiff catheters and clinical touch respectively.

The ET catheter has to pass through the endocervical canal to go into the uterine cavity through the internal os. The endocervical canal may be filled up with mucus or blood. Embryos trapped in the mucus or blood after the passage of the endocervical canal may not be able to implant into the endometrium. Guardia™ Pro Protective ET catheter is designed to allow the safe passage of embryos through cervical mucus and blood as its outer sheath protects the embryo through entry and then opens in petals to further advance the inner catheter and gently place the embryo.

There is still no study comparing conventional and protective ET catheters in terms of the pregnancy rate of IVF treatment. The hypothesis of this study is that the pregnancy rate is significantly higher after ET using protective ET catheters.

Research plan Patients attending the Department for IVF-ET will be recruited if they fulfill the inclusion criteria and do not have the exclusion criteria. The FET treatment will be arranged as indicated.