Improving IVF Results: How Far Can We Tamper with Human Biology?

  • Pasquale PatrizioEmail author
  • Sherman Silber
Part of the Reproductive Medicine for Clinicians book series (REMECL, volume 1)


Modern IVF is allowing couples to have children who otherwise would remain childless. However, human reproduction is inherently inefficient and assisted reproductive technologies (ARTs) cannot overcome this biological limit. In fact, despite what appears superficially to be continual improvement in IVF results, there may be an ultimate limit to the reproductive potential of the human oocyte. In fact, the great majority of oocytes (about 90%) harvested after ovarian stimulation and many embryos (about 80%) produced during ART and transferred, do not result in a live birth. In contrast, recent experience from oocytes retrieved for IVF in natural cycles, i.e., without stimulation, followed by single-embryo transfer, has demonstrated much less oocyte and embryo wastage rates, with about 25% of the oocytes (up to age 37) able to produce a live birth and then gradually declining as women age, completely in line with rates of natural fecundity. However with aggressive ovarian stimulation protocols, the collection of many oocytes is associated with an increased biological wastage since many are not able to result in a live birth. Properly validated embryo selection methods, not available at the time of this writing, would be keys to higher pregnancy rates per transfer, but not per patient.


Oocyte-to-baby rate Embryo wastage Reproductive efficiency Blastocyst 


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Copyright information

© IAHR (International Academy of Human Reproduction) 2018

Authors and Affiliations

  1. 1.Yale University Fertility CenterNew HavenUSA
  2. 2.Infertility Center of St. Louis, St. Luke’s HospitalSt. LouisUSA

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