The cumulative probability of liveborn multiples after in vitro fertilization: a cohort study of more than 10,000 women

Objective: To estimate the cumulative probability of liveborn multiples after IVF to improve patient counseling regarding this significant morbidity.

Design: Retrospective cohort study.

Setting: Large academic-affiliated infertility practice.

Patient(s): A total of 10,169 women were followed from their first fresh, nondonor IVF cycle through up to six fresh and frozen IVF cycles from 2000-2010.

Intervention(s): None.

Main outcome measure(s): Delivery of a liveborn infant(s).

Result(s): After three IVF cycles the cumulative live birth rate (CLBR) was 53.2%. The singleton, twin, and triplet CLBRs were 38.0%, 14.5%, and 0.7%. After six IVF cycles the CLBR was 73.8%, with 52.8%, 19.8%, 1.3% for singletons, twins, and triplets. Of the 5,433 live births, 71.4% were singletons, 27.1% were twins, and 1.5% were triplets. Women more than 39 years had the lowest incidence of liveborn multiples with CLBRs of 5.2% after three cycles and 9.5% after six cycles. The twin CLBR doubled from cycles 1 through 3 with the rate of increase slowing from cycles 3 through 6. Although very low in absolute terms, the triplet CLBR also doubled from cycles 1 through 3 and doubled again from cycles 3 through 6. Of the 1,970 pregnancies that began as multifetal on ultrasound, 77.4% resulted in liveborn multiples.

Conclusion(s): Providers should be aware of the cumulative probability of liveborn multiples to effectively counsel patients on this important issue. With nearly three-quarters of all women having live birth after up to six IVF cycles, it is encouraging to report a low incidence of liveborn multiples.