Why was the ultrasound performed? It if was performed because she was pregnant and bleeding, you would have to use an ob ultrasound code because they are evaluating the status of the pregnancy (which the documentation could imply). This coding advice is true (per CPT Assistant article) whether the patient is found not to be pregnant after the exam. If they were only evaluating abnormal bleeding for gyn purposes, you would use 76857.
From the 2001 CPT Assistant:
To clarify, for female patients with an established diagnosis of pregnancy, determined by any method, and with indications for the ultrasound procedure that might be pregnancy related, it is appropriate to report an obstetrical ultrasound code from the 76805-76815 series.
For a patient with an established diagnosis of pregnancy (determined by any means), with signs and symptoms that could be pregnancy related and necessitating an ultrasound evaluation of the pelvis, the obstetrical ultrasound code(s) 76805-76815 should be reported, even if the outcome of the procedure is that the patient is now not pregnant or has an ultrasonic diagnosis that might be construed as being independent of the pregnancy (eg, acute appendicitis, torsed ovary, necrotic fibroid).
Pelvic Ultrasound Coding
If a female patient without an established diagnosis of pregnancy presents with gynecological problems necessitating ultrasound evaluation (eg, dysmenorrhea, oligomenorrhea, menstrual irregularity, pelvic pain, etc.), then it is appropriate to report a pelvic ultrasound code 76856 or 76857. The use of codes 76856 or 76857 is not predicated upon whether or not the outcome of the ultrasound procedure is the diagnosis of pregnancy or a complication related to a pregnancy.