Under the Microscope: An Examination of Embryo Transfer Technique
Assisted reproductive technology (ART) has allowed millions of couples to bear children over the last 40 years, but it remains less than 100% successful. Attention has focused on improving ovarian stimulation, insemination methods, culture techniques, and screening for genetic status of resulting embryos. These measures have increased pregnancy outcomes year by year, allowing for single embryo transfer as the standard approach in many instances.
It is indisputable that the embryo transfer technique (ET) itself is a vital component of the process. It seems however that the technical aspects of embryo transfer have been “below the radar” for many ART practitioners. The World Egg Bank has known that there is a learning curve and that some operators have consistently better outcomes than their colleagues in the same practice. One concern is many fellows in US training programs perform very few ET procedures, leaving new graduates to learn on their patients. After recognizing this, the American Society for Reproductive Medicine (ASRM) commissioned the development of an ET trainer device, a virtual reality based simulator. A recent study showed that use of the simulator shortened the learning curve considerably for fellows (Embryo transfer simulation improves pregnancy rates and decreases time to proficiency in Reproductive Endocrinology and Infertility fellow embryo transfers. Heitmann, Ryan J. et al. Fertil Steril, 2017; 107, 1166 ).
Many standard techniques of ET have never been rigorously evaluated, and when they have, the results have been somewhat inconsistent. ASRM formed an Embryo Transfer Advisory Panel, seeking to improve performance of the ET by utilizing a combination of literature search and surveying Society for Assisted Reproductive Technology (SART) member practices regarding their use of various procedures. The findings have recently been published (ASRM standard embryo transfer protocol template: a committee opinion. Penzias, Alan et al. Fertil Steril, 2017; 107, 897 – 900).
The conclusions are slightly surprising and definitely worth review. Turns out that only a handful of the component steps of the ET practice are proven to be beneficial, for example transabdominal ultrasound guidance and use of a soft catheter. A few commonly employed practices such as, bed rest after ET and powder-free gloves have been demonstrated not to be beneficial. The benefits of a number of other practices are still unclear.
After review, the Practice Committee issued guidance for the basic approach to the embryo transfer technique. The Committee also reminds us of the many benefits of standardization of clinical methods, recommending that each ART program develop a set of standard procedures to reduce risk and to optimize outcomes. It is time well spent for IVF practitioners to review these guidelines and discuss them with their clinical teams.
