Does it really matter how far from the fundus embryos are transferred?

Area of Science:

• Reproductive Medicine
• In Vitro Fertilization (IVF)

Background:

• Embryo transfer (ET) is a critical step in IVF, with procedure details potentially influencing outcomes.
• Transfer depth has been investigated as a factor affecting clinical success.

Purpose of the Study:

• To assess the association between embryo transfer depth, indicated by air bubble location, and IVF clinical outcomes.
• To determine if the distance of embryo placement from the uterine fundus correlates with implantation and pregnancy rates.

Main Methods:

• Retrospective analysis of 409 IVF cycles in good prognosis patients.
• Embryo transfer depth was assessed using air bubble location as a surrogate marker.
• Correlation of transfer distance with implantation rates (IR) and pregnancy rates (PR) for day 3 and day 5 transfers.

Main Results:

• No significant difference in pregnancy rates was observed between cycles with successful pregnancies and those without (6.7mm vs 6.5mm).
• Implantation and pregnancy rates were comparable whether embryo transfer occurred in the upper or middle third of the uterine cavity.
• Transfer depth did not influence implantation rates when analyzed separately for cleavage stage and blastocyst stage embryos.

Conclusions:

• Embryo transfer depth in the middle or upper third of the uterine cavity does not appear to affect implantation and pregnancy rates in IVF.
• These findings suggest that precise depth control within these regions may not be crucial for successful IVF outcomes.