I'd stick with a wedge heel, more stability. Remember what it's like when you are puffy and swollen and not to mention your center of gravity is off with baby in tow.
I think kitten heels might be a bit daunting, I remember I had such a hard time walking in real heels when I was preggers. And if you are remotely afraid of that puffyness at all, stay away from the ankle straps! Nothing is more unattractive then when someone's ankles swell around those straps!