Glossary · Definition · v2026.3
Live Birth Rate in IVF
Live birth rate is the percentage of initiated cycles, retrievals, or embryo transfers resulting in at least one live-born infant. The denominator used changes the reported rate substantially.
How Live Birth Rate Is Measured
Live birth rate can be reported per cycle start, per retrieval, or per transfer. Per-transfer rates are highest because they exclude patients who never reached transfer. Per-retrieval rates include all patients who started but account for cancellations and failed fertilization. Per-cycle-start is the broadest and lowest denominator. CLBR (cumulative live birth rate) evaluates all transfers from a single retrieval, providing the most meaningful planning metric.
Biological Constraints
Live birth rate is a population statistic and does not predict individual outcomes. Age, diagnosis, embryo quality, and laboratory performance all influence the rate. Comparing rates between clinics requires matching on denominator, patient population, and methodology.
Related reference
Used in
This content defines terminology for educational orientation. It does not constitute medical advice.
IVF Daddies Newsletter
Structural briefings on policy, clinical, and regulatory developments.
Weekly updates on family-building governance.