Some organisations like to see candidates do a presentation. The topics will vary, from something knowledge or technical based to your perspective or opinion on something relevant to your practice as a midwife. You are most likely to be told in advance what the presentation will be on so you have time to prepare.
Usually it is how you formulate your key points and present your arguments that assessors are most interested in, and not necessarily how many facts and figures you have memorised. You need to set yourself a clear structure for what you want to cover and make sure you speak slowly and confidently, sticking to your topic (without wandering off on a tangent!) It’s most useful to plan some key headings rather than memorise the entire content; you are likely to know the topic you are presenting on, all you have to do is to decide what you personally want to cover.