Successful embryo transfer: Why technique and catheter choice matter

Embryo quality remains the strongest predictor of IVF success, particularly embryo euploidy and developmental competence. However, even the highest-quality embryo requires optimal conditions to implant successfully. Evidence shows that embryo transfer (ET) technique, uterine health, and catheter selection can all influence clinical outcomes.

Successful embryo transfer depends on four key factors:
•    Embryo competence
•    Endometrial receptivity
•    Uterine environment
•    Transfer technique

Before transfer, uterine abnormalities should be identified and treated where appropriate. In all embryo transfer cycles, adequate progesterone exposure and embryo-endometrial synchrony are also essential for implantation.

From a procedural perspective, clinical guidelines consistently support ultrasound guided embryo transfer and the use of soft atraumatic catheters, to minimise cervical and endometrial trauma.^1,2 Furthermore, using a high concentration of hyaluronan rich media can have a positive outcome.^3,4 These practices are associated with improved implantation and pregnancy outcomes.

What clinicians look for in an embryo transfer catheter

While embryo transfer catheters may appear simple, their design can have a meaningful impact on procedural efficiency and ease of transfer. Feedback from IVF professionals highlights five key features that influence catheter selection:⁶

• Soft inner catheters are preferred because they reduce the risk of cervical and endometrial trauma, helping facilitate smoother transfers.
• Depth markings and echogenic catheter tips improve visualization during ultrasound-guided procedures, allowing for more precise embryo placement.
• Pre-curved or specially designed guide catheters can help clinicians navigate challenging cervical anatomy while minimising uterine irritation.
• Catheters that are easy to load, handle, and manipulate are valued by both embryologists and clinicians, supporting procedural consistency.
• Consistent performance, high-quality materials, and dependable manufacturing are critical considerations when selecting a catheter. Cost remains a factor, but reliability is often prioritized.

Beyond technique: The role of transfer media

Evidence also supports the use of hyaluronan-rich transfer media, such as EmbryoGlue®, which has been associated with improved implantation, clinical pregnancy, and live birth rates in several systematic reviews and meta-analyses.⁴ Benefits are particularly evident in women aged 35 years and older and in patients with previous implantation failure.⁵ Furthermore, a hyaluronan-rich transfer medium, such as EmbryoGlue is recommended as an add on by ESHRE.⁶

Conclusion

While embryo competence remains the primary determinant of IVF success, optimising the transfer procedure can further enhance outcomes. Careful attention to uterine health, evidence-based transfer techniques, and thoughtful catheter selection can help support a smooth, atraumatic, and precise embryo transfer, ultimately creating the best possible conditions for implantation.

 References 

1. Practice Committee of the American Society for Reproductive Medicine. Performing embryo transfer: a guideline. Fertility and Sterility. 2017;107(4):882–896.
2. D'Angelo A, et al. Evidence-based guideline recommendations on embryo transfer practice. Human Reproduction Open. 2022;hoac038.
3. Tyler B, et al. Interventions to optimize embryo transfer in women undergoing assisted conception: a comprehensive systematic review and meta-analyses. Human Reproduction Update. 2022;28(4):480–500.
4. Heymann D, et al. Hyaluronic acid-enriched embryo transfer medium for assisted reproductive technologies. Cochrane Database of Systematic Reviews. 2020.
5. Urman B, et al. The impact of hyaluronan-enriched transfer medium on IVF outcomes. Fertility and Sterility. 2008.
6. Vitrolife data on file. Survey 2022-23 in Europe.
7. Lundin K, et al. ESHRE Good Practice Recommendations on Add-ons in Reproductive Medicine. Human Reproduction. 2023.