I am not sure of your situation or why your ob has requested you have one but a Biophysical is an ultrasound that measures your amniotic fluid, your babies movement and your looks at your babies practice breathing. I had a few of these ultrasounds with my DD and all came back fine. Was he concerned about your level of amniotic fluid? You levels may be on the lower side of normal. That is what I would be putting it down to. Do not stress yourself about it, he would have told you if there was something wrong. Maybe just ask the purpose at your next appointment.

Yay on having another precious girl