Is a vaginal ultrasound necessary?

Cm
Last time I had one was the first time I became pregnant and didn't know anything about ob procedures. They did the vaginal ultrasound and I immediately started bleeding afterward and didn't stop for a couple of days. 
That pregnancy ended in miscarriage. I am not saying that is what caused it but I would rather be safe than sorry. 
Can I just refuse it? If so, when can hear/see my baby's heart beat with just a regular ultrasound ?