At what stages do they give you ultrasounds during your pregnancy?

At what stages do they give you ultrasounds during your pregnancy?
Question by mums_the_word: At what stages do they give you ultrasounds during your pregnancy?
I haven't had one yet... I have my first on wednesday! So excited! I'll be 12 weeks then. I was just wondering about how many ultrasounds do you typically have during a pregnancy and at what weeks are they normally? I ask because my partner and I are separated at the moment (due to my parents lack of support of our relationship... but

ultrasounds during your pregnancy