Here at Manchester Fertility we don't offer routine Natural Killer cell testing as, - in line with the opinion from the HFEA - it has no proven benefit. Some of our patients are faced with recurrent implantation failure and early miscarriages where we use a standard quad therapy (high dose progesterone, low dose steroid and heparin and low dose aspirin). In some cases we cooperate with Professor Quenby in Warwick who is a renowned scientist of this field.