Embryonic aneuploidy rates are equivalent in natural cycles and gonadotropin-stimulated cycles

The prevalence of embryonic aneuploidy is the same in natural cycles and those employing superovulation. Prior concerns that exogenous gonadotropins increase embryonic aneuploidy are unsupported by this data.

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Volume 112, Issue 4, Pages 670–676


Kathleen H. Hong, M.D., H.C.L.D., Jason M. Franasiak, M.D., H.C.L.D., Marie M. Werner, M.D., H.C.L.D., George Patounakis, M.D., Ph.D., Caroline R. Juneau, M.D., Eric J. Forman, M.D., H.C.L.D., Richard T. Scott Jr., M.D., H.C.L.D.



To determine if natural selection and follicular stimulation produces a lower risk for embryonic aneuploidy than that attained following superovulation with exogenous gonadotropins.


Prospective observational with historical control group.


Large academically affiliated private practice.


All patients presenting for their evaluation for infertility were offered participation in the study.


All participants in the natural cycle group underwent an unstimulated in vitro fertilization (IVF) cycle. A subsequent frozen embryo transfer was performed if a euploid blastocyst was attained.

Main Outcome Measure(s)

Rates of embryonic aneuploidy attained in unstimulated IVF cycles were compared to those observed in age-controlled historical cohort undergoing conventional stimulated IVF cycles with exogenous gonadotropins.


Aneuploidy rates were equivalent in unstimulated and stimulated IVF cycles. The prevalence of aneuploidy in natural cycles increased with the age of the female partner in a manner identical to that seen in stimulated IVF cycles. Finally, sustained implantation rates of euploid blastocysts were equivalent in natural and stimulated IVF cycles.


Rates of embryonic aneuploidy are not impacted by follicular stimulation with exogenous gonadotropins. Prior concerns of inducing a higher risk of embryonic aneuploidy are not supported by this data.

Clinical Trial Registration Number


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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.