Standardization of catheter load speed during embryo transfer: comparison of manual and pump-regulated embryo transfer

The position of transfer air bubbles after embryo transfer is related to the pregnancy rate. With the conventional manual embryo-transfer technique it is not possible to predict the final position of the air bubbles. This position mainly depends on the catheter load speed at transfer (injection speed), a parameter that remains uncontrollable with the conventional technique even after standardization of the protocol. Therefore, the development of an automated device that generates a standardized injection speed is desirable. This study aimed to examine the variation in injection speeds in manual embryo transfer and pump-regulated embryo transfer (PRET). Seven laboratory technicians were asked to perform simulated transfers using the conventional embryo-transfer technique. Their injection speeds were compared with that of a PRET device. The results indicate that in manually performed transfers, even after standardization of the protocol, there is still a large variation in injection speed, while a PRET device generates a reliable and reproducible injection speed and therefore brings new possibilities for further standardization of the embryo-transfer procedure. Future research should reveal whether these experiments mimic real clinical circumstances and if a standardized injection speed results in more exact positioning of the transferred embryos and therefore higher pregnancy rates.The position of transfer air bubbles after embryo transfer is related to the pregnancy rate. With the currently used embryo-transfer technique, in which embryos are transferred manually with a syringe, we are not able to predict the final position of the air bubbles. This position depends on the injection speed of the syringe, which remains uncontrollable in embryo transfers that are performed manually even after standardization of the protocol. Therefore we developed an automated device that generates a reliable and reproducible injection speed, a pump-regulated embryo transfer (PRET) device. This study aimed to examine the variation in injection speeds in transfers performed manually and with the PRET device. Our results indicate that in manually performed transfers, even after standardization by protocol, there is still a large variation in injection speed and that the PRET device generates a reliable and reproducible injection speed and therefore brings new possibilities for further standardization of the embryo-transfer procedure. Future research should reveal whether our experiments mimic real clinical circumstances and if a standardized injection speed results in more exact positioning of the transferred embryos and therefore higher pregnancy rates.