No it doesn't hurt at all. The length of time varies from scan to scan, but about half an hour is about average i'd say. Sometimes with wriggly babies it can take a bit longer. Take something to keep her occupied, book, toy etc. If you are going to a children's hospital, they often have TV's and things in the room, although at 10 months she may not be interested in that.

The blood test is never fun with a baby, but it is over pretty quickly. I took a special treat to give my DD for straight after. She cheered up pretty quickly. Best of luck. x