The cumulative probability of liveborn multiples after in vitro fertilization A cohort study of more than 10000 women

Multiple-gestation pregnancies are the most significant morbidity after IVF, yet national data reports outcomes as per cycle pregnancy rates. This study provides estimates of the cumulative incidence of liveborn multiples and reports a low cumulative incidence of liveborn multiples, especially triplets.

Beth A. Malizia, M.D., Laura E. Dodge, M.P.H., Alan S. Penzias, M.D., Michele R. Hacker, Sc.D.

Volume 99, Issue 2, Pages 393-399, February 2013


To estimate the cumulative probability of liveborn multiples after in vitro fertilization (IVF) to improve patient counseling regarding this significant morbidity.

Retrospective cohort study.

Large academic-affiliated center.

A total of 10,169 women were followed from their first fresh, non-donor IVF cycle through up to 6 fresh and frozen IVF cycles from 2000-2010.


Main Outcome Measures:
Delivery of a liveborn infant(s).

After 3 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 6 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 over 39 had the lowest incidence of liveborn multiples with CLBRs of 5.2% after 3 cycles and 9.5% after 6 cycles. The twin CLBR doubled from cycles 1 through 3 with the rate of increase slowing from cycles 3 through 6. While 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.

Providers should be aware of the cumulative probability of liveborn multiples in order to effectively counsel patients on this important issue. While nearly three-quarters of all women had a live birth after up to 6 IVF cycles, it is encouraging to report a low incidence of liveborn multiples.

  • NicoGarrido

    Thank you for your answer to our comments!

    I am keen to read your next work

    all the best


  • NicoGarrido

    Dear Dr Malizia,
    congratulations for your nice work.
    The approach of using KaplanMeier curves with multiple pregnancies as the main even measured provides with very useful information to the community.
    Our group has published a couple of papers with a similar approach, computing the cumulative livebirth rates per embryo transferred in consecutive IVF cycles.
    This leads me to think that in your paper, a very interesting information can be provided categorizing the results per number of embryos transferred, obviously from two onwards.
    This information can also be helpful to describe with precision the likelihood of double, and high order pregnancies whe more than one embryo is transferred.
    Do you think this can be a good idea?
    thank you!

    • Beth A. Malizia, MD

      Thank you for your comments. We hope that physicians and clinics counseling women regarding their multiple pregnancy rate will find the curves helpful. Given the restraints of the Kaplan Meier analysis we are only able to apply one variable (in our case maternal age) to the analysis and were not able to stratify by both age and embryo transfer number. However, we do report an embryo transfer number (2.1 to 2.6) which may be lower than the national average given that the study was completed in a state which has an insurance mandate for fertility coverage. We hope that the results of this study including a low triplet cumulative live birth rate of 1.3-1.5% will continue to encourage steps to reduce the multiple pregnancy and live birth rate from IVF both through the transfer of fewer embryos as well as programs (such as insurance coverage) to decrease the financial pressure patients and clinics are under to transfer more embryos for a higher pregnancy rate. Thank you again for your interest in our work.

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