Add-ons are “extras” used in IVF because it is hoped they might improve success rates. Add-ons can be considered as belonging to two groups; those used during the making or selection of embryos and those that aim to improve the interaction between the embryo and the womb lining (or implantation). Add-ons from the former group include Physiological ICSI (PICSI, a modified form of ICSI where sperm undergo a selection test prior to ICSI), Preimplantation Genetic Testing for Aneuploidy (PGT-A) and Timelapse Embryo Monitoring. Add-ons aimed at improving implantation include Natural Killer (NK) Cell testing, Endometrial Scratching and Embryo Glue.
The reality about add-ons is that they are expensive and evidence is very unclear whether they can definitively improve pregnancy chances. Indeed, in some cases, like PICSI and endometrial scratching, there is evidence from recent large clinical trials that they don’t improve outcomes. More worrying, is that recent data suggest that PGT-A could actually worsen outcomes for some patients. Before including an add-on, there should be careful discussion about why it is being used and how it will benefit your treatment.