Typically, a female dog ovulates sometime around day 9-14 of her estrus cycle. This is also when the bloody discharge appears to dry up, but then it returns for the final third of the heat. If it was during this middle part of the season when she mated, then pregnancy is likely. If, however, it was when she was coming to the end of her season (day 21 plus), then ovulation is less likely but not impossible, so the risk of pregnancy decreases.