Fertility treatment can be an expensive business. Reporter Deborah Cohen investigates how some clinics sell add-ons - the extra drugs, tests and treatments offered on top of standard fertility care. Some can add hundreds or thousands of pounds to a bill. Exclusive new research shows a worrying lack of good evidence from trials to show these can improve the chances of having a baby. Panorama goes undercover to reveal how patients aren't always told everything they need to know when they ask some clinics about these treatments.