November 26th, 2022

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Projections of Population-Based Twinning Rates Through the Year 2100
Authors:  Jaroslaw J. Oleszczuk, M.D., Donald M. Keith, M.B.A., Lt Col (Ret), and Louis G. Keith, M.D. William F. Rayburn, M.D. Section Editor
  OBJECTIVE: To present the first compilation of population-based twinning rates
published after the year 1990 and to project population-based twinning rates
through the year 2100.

STUDY DESIGN: We searched the Internet-based MEDLINE database for articles
published after 1990 in which population-based twinning rates were described. We
used population-based data from national statistical authorities from Australia,
Austria, Canada, Finland, Hong Kong, Israel, Japan, Norway, Singapore and
Sweden, published by Y. Imaizumi in a recent article. U.S. figures were based on
data from the National Center for Health Statistics. Annual growth rates of
twinning were calculated and graphed, making the assumption that these rates
would remain constant throughout the next century.

RESULTS: Our report presents the most recent population-based twinning rates.
When projected through the year 2015, twinning rates reach figures that could
best be described as derived from a Jules Verne novel: Sweden, in this model,
would have four times more twin than singleton births.

CONCLUSION: We strongly suggest that physicians reexamine their patterns of
prescribing ovulation-inducing agents, which carry a greatly increased risk of
multiple pregnancy. (J Reprod Med 1999;44:913-921)
Keywords:  twins; twin studies; twins, dizygotic; twins, monozygotic
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