P-314: Do interventions necessary to overcome technical difficulties encountered in trial embryo transfer and employed during real embryo transfer really improve outcome in IVF cycles?

Abstract

To evaluate the impact of intervention techniques employed in real embryo transfer to overcome technical difficulties presented during trial transfer on the outcome of IVF cycles. Prospective observational study of 418 consecutive IVF/ET cycles. Trial embryo transfer (TET) to map the cervical canal was performed with a soft polyethylene catheter and a firm outer Teflon introducer (Wallace, SIMS Portex, UK) in all cycles immediately before the real transfer. All trial and real embryo transfers (RET) were performed under abdominal ultrasound guidance 72 hours after oocyte retrieval and only RETs considered uneventful (n=364) were compared. Interventions suggested by TET that were employed in RET to overcome difficulties included the use of: Group A (n=184)- soft catheter, no interventions; Group B (n=97)- soft catheter, insertion of the outer introducer through the endocervical canal and internal os, with or without the help of a tenaculum and; Group C (n=83)- firm catheter (Tefcat, Cook, USA), with or without the help of a tenaculum. All catheters were loaded with a maximum of four embryos in 20-30μl of culture medium after embryo morphology evaluation and grading. After RET, the following variables were recorded: presence of blood and/or mucus in or on the transfer catheter; cramping or patient discomfort; retention of embryos in the transfer catheter. There was no difference between groups with respect to patients’ main demographic and baseline characteristics, embryo development rate, mean number and quality at transfer. The overall clinical pregnancy rate/transfer for the different interventions was 48.4%, 41.2% and 25.3% in groups A, B and C, respectively, showing a significant difference (p=0.02) between groups A and C. Likewise, the implantation rate was significantly higher (p=0.005) in group A (26.2%) than in group C (15.6%) and revealed a trend (p=0.08) toward better results when compared to group B (19.7%). Clinical pregnancy/implantation rates showed no difference when groups B and C were compared. Contamination of the catheter with blood and/or cervical mucus was more frequent in group B (68.0%) when compared to groups A (37.5%) and C (41.0%) (p=0.0001, p=0.0004; respectively). The occurrence of uterine cramping was 3.6%, 10.2% and 18.6% in groups A, B and C, respectively, showing a significant difference (p=0.001) between groups A and C and no difference when groups A and B or B and C were compared. There was no difference between groups in regard to the incidence of retained embryos. The use of more invasive and potentially traumatic interventions by clinicians to efficiently overcome a difficult TET during RET may, by themselves, significantly impair the outcome of IVF cycles. This is reflected in the lower pregnancy and implantation rates observed in the study, regardless of degree of ease in execution of the procedure. Every maneuver should be tried with a softer catheter before changing it to a firmer one, since it is clearly shown by this study that the latter has a negative impact on the overall outcome. A balance between the choice of the intervention necessary to overcome the difficulties encountered during TET, and the expected decrease in pregnancy/implantation rates should always be taken into account by the clinician in charge of the embryo transfer, since different intervention techniques may have negative influence on the outcome of IVF cycles to varying degrees.