How common for the first mammogram to come back abnormal?

Not common: This is not very common. Mammograms are easier to interprete when the patient hasd prior mammograms for comparison, for any interval changes. Occasionally when it is the baseline mammogram (ie first mammogram) it may be difficult determine if something has been there before or not and additional evaluation may be needed.

Abnormal baseline: A recent large study found that the overall percentage of recalls(extra views) for nonbaseline mammograms was 11.5% (range, 9.6 %-24.9%), and the overall percentage of recalls for baseline exams was almost three times as high, at 28.4% (range, 18.4%-60.3%). Biopsy recommendations following diagnostic workups were also greater for baseline (5.2%) than nonbaseline (1.8%) exams.