Live birth rate is the percentage of all IVF cycles that lead to live birth, and is the pregnancy rate adjusted for miscarriage and stillbirth. These percentages are for successful pregnancies, regardless of the number of children born, as twins and larger multiple-order births are more common in IVF cycles.
Pregnancy rate is the success rate for pregnancy. For IVF, it is the percentage of all attempts that lead to pregnancy, which generally refers to treatment cycles where eggs are retrieved and fertilised in vitro. Statistics referring to “pregnancy” may refer to just a positive pregnancy test, and not necessarily “viable pregnancy” which implies the detection of a fetal heart beat.