Temperature fluctuations during embryo transfer can be mitigated by optimizing transfer protocol

Research Question What impact do variations in embryo transfer catheter loading and movement procedures have on temperature and pH fluctuations during embryo transfer? Design Mock embryo transfers were conducted to test the impact of airflow/movement, use of catheter coverings and the type of workstation used for catheter loading on catheter temperature. A thermocouple probe inserted into the tip of the outer catheter or taped to the exterior of the inner catheter recorded temperature within the catheter every 5 sec from time of mock embryo loading (TL) up to 60 sec (TL +60s). Fluctuations in culture medium pH in embryo transfer dishes were monitored. Results Catheter temperature was lower at TL+15s (26.8 ±0.61°C) than TL (30.5 ±0.81°C, P <0.05). The rate of cooling during transit was slower when catheters were covered to reduce the cooling effect of air movement (P<0.05). Temperature was better maintained when catheters were loaded in a crib compared to a heated stage, until initiation of transit, when the rate of temperature decrease was similar. Culture medium pH increased faster when embryo transfer dishes remained on a heated stage during the procedure compared to within an open crib. Conclusions Temperature loss during the ET procedure can be mitigated by reducing transit time and using catheter coverings. Use of a crib for catheter loading only improved temperature stability while the catheter remained in the crib, not during transit, and it reduced pH fluctuations during the procedure.