How many weeks along do you have to be to get an ultrasound without it hurting your potential child?

it doesn't matter how many ultrasounds you have when youre pregnant. I know this because i am a high risk pregnancy and i get one every two weeks and my doctor would never do that if it were dangerous. There is also no reason you couldnt have one very early on. the reason why most physicicans wont do one this early is because its not going to show much. if you suspect you are about 4 weeks, your baby hasn't even latched on to the uterus. Your doctor will probably choose to do a blood test because its 100% accurate. when they take your blood they test the HCG levels (a hormone that starts releasing right after conception) .. this is why the blood test is never wrong.