How early can you see a baby on an ultrasound? i was looking up the dates, and when i had intercourse, it was in july, sometime before the 28th, the 28th is when i went for my ultrasound and said they saw nothing, And the blood test was negative, BUT my urine test was positive, is it because it was too early? thats what im thinking, cause i would only be two or three weeks when i went.