Routine embryo transfer in the IVF laboratory

Background In a very real sense, there is nothing routine about an in vitro fertilization (IVF) embryo transfer. It is the final and critical step in a patient’s fertility treatment that has enabled millions of infertile couples to realize their dream of having a child. After completing all steps up to this point as part of their IVF cycle, it is the embryo transfer on which the entire process of bringing a new life into the world depends. A key to a smooth embryo transfer is an experienced and engaged embryologist. Depending on the laboratory workflow, the embryologist may choose embryos for transfer, move embryos into the transfer dish, load the catheter with embryos and hand off the catheter to the clinician for transfer into the uterine cavity. Every step of the embryo transfer is critical and requires attention to detail and the ability to troubleshoot any issue that may arise. Embryologist Experience The embryologist must be trained and have acquired embryo transfer experience under supervision before performing transfers independently. While each laboratory has its own training regimen, it is important that embryologists observe transfers (n = 20), perform transfers under supervision (n = 20) and have pregnancy rates within two standard deviations of the mean pregnancy rate for the programme prior to being authorized to do transfers alone. During their training, embryologists should also become aware of how to troubleshoot unforeseen problems such as embryo return, re-loading of embryos and options for difficult transfers. Reagent and Supply Inventory At all times, a supply of catheters and syringes should be available for embryo transfer. There are a number of catheter options available commercially, and often the choice of catheter is clinician specific. Catheters typically come packaged with an outer sheath that contains a longer inner flexible catheter with an open lumen. The outer sheath and the inner catheter can be connected to each other via fitting their hubs together at the top and leaving the inner catheter protruding and visible at the open end. A tuberculin syringe is attached to the catheter collar at the top, and the syringe plunger is manipulated to both aspirate and expel the contents of the inner catheter.