Early Pregnancy Success Rates

Everyone online is always wondering when certain positives are linked with a reduction in the chance of pregnancy loss -- and a greater chance of having a baby. I've looked it up an found these references:

The loss rate after a normal scan was similar in symptomatic (10.6%) and asymptomatic patients (9.1%) and declined progressively with gestational age from 17.0% at 6 to 7.9 weeks to 4.3% at 12 to 13 weeks (P < 0.01, chi-squared).
From: Pregnancy outcome after a first trimester sonogram demonstrating fetal cardiac activity.

The pregnancy outcome of 347 patients with a confirmed, viable intrauterine pregnancy between 6.0 and 14.0 weeks, menstrual age, was determined. The miscarriage rate was 4.2% in a subgroup of patients without vaginal bleeding, as compared with 12.7% in a subgroup with bleeding
From: Fetal loss rate after ultrasonically documented cardiac activity between 6 and 14 weeks, menstrual age.

This one isn't an easy read, but it sort of looks like, in the absence of bleeding, the rate is around 4-5% chance of pregnancy failure after the detection of fetal heart activity. With bleeding it's a little more touch and go, with the miscarriage rates ranging from 11-16.5%.