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

Abstract

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.

Embryo Transfer Catheters: Softer is Easier

“…• Operator experience (Groeneveld et al, 2012;Kably Ambe et al, 2011;Karande et al, 1999;Lu et al, 1999;Hearns-Stokes et al, 2000;Yao et al, 2009). …”

Embryo Transfer with Controlled Injection Speed to Increase Pregnancy Rates: A Randomized Controlled Trial

“…1). This device enables a better controlled positioning of the embryo(s) inside the uterine cavity, extensively described by Groeneveld et al [25]. The results of this in vitro study strongly indicated that the PRET device generates a reliable and reproducible injection speed and pressure and, therefore, brings new possibilities for further standardization and potential optimization of the embryo transfer procedure, compared to the manually performed embryo transfer.…”

“…In a manually performed embryo transfer, the inner catheter was loaded and unloaded by the laboratory technician using a simple syringe; in a PRET, the syringe was replaced by the PRET device. The PRET device is developed to perform the embryo transfer in a standardized and reproducible way; the technical aspects of the PRET device were previously described by Groeneveld et al [25]. The inner catheter is connected to the PRET device and loaded by the laboratory technician using the device's scroll-wheel interface.…”

“…This injection speed affects the depth and placement of the embryo in the uterine cavity and is shown to be highly variable in, and between subjects, in a manually performed embryo transfer with a syringe [25]. In an effort to standardize the injection speed during embryo transfer, we developed an automated device that generates a standardized injection speed, the pump-regulated embryo transfer (PRET) device, in co-operation with the Delft University of Technology (fig.…”

“…Given the results of the study of the injection speed in vitro by Groeneveld et al [25], we conducted a randomized controlled trial to investigate whether this standardization of the injection speed and pressure results in a better controlled positioning of the transferred embryo(s) in vivo. Both the safety of clinical use and effect on pregnancy rates were investigated.…”