Share 'Ultrasounds...how many are necessary?'

I am beginning week six of my first pregnancy and interesting in having what I call a 'naturally informed' pregnancy. Watching The Business of Being Born almost a year ago (before I was even pregnant!) solidified the path I want to take My question is about ultrasounds. It seems to me that it has become almost required to have numerous ultrasounds throughout pregnancy. I asked my ob what the min…