First appointment with midwife

So my first appointment with my midwife is on Sunday... I should be exactly 8w then. My midwife says I'm only required one ultrasound at 20w but I see a lot of women saying they do ultrasounds at first apt to find a heart beat and make sure its not ectopic and what not so I'm wondering how to midwives do it? Dont they still need to measure and estimate due date and everything?