Hi My Wife Is Approx 1-2 Weeks Pregnant (confirmed By

Hi my wife is approx 1-2 weeks pregnant (confirmed by recent blood test also). Following a vaginal ultrasound (which showed nothing as yet and were told that it was too early) she had some brown spotting with a little red blood (minimal only when wiping) for the following 2 days. She did not experience any significant cramping. Any cause for concern? Could the minimal bleeding be caused by the ultrasound or is it a sign of miscarriage?