Bad idea! Ultrasounds are an invasive proceedure that have been linked to brain damage (http://www.mercola.com/2001/dec/19/ultrasound.htm). The more ultrasounds you have done the higher the risk. Better to make sure you have good and early pre-natal care and nutrition and trust that God/Millions of Years of Evolution (take your pick) will ensure a healthy baby.

While it might not be the greatest thing to ultrasound a developing baby wouldn't know not being a doctor. But this could still be a useful home medical devices it could be use for injuries to determine if it's a break or not and such. It would need an easily operable interface some type of image augmentation and would really shine in tele-medicine.