Fresh versus frozen: initial transfer or cumulative cycle results: how do we interpret results and design studies?
The way we practice assisted reproductive technology has changed over time. In many ways these changes have been positive as technology has improved, in vitro culture has improved, and embryo selection increasingly allows a single embryo transfer with high success rates and ever smaller multiple birth rates. However, our specialty has often been criticized for not being critical with respect to the acceptance of new technology. Although the outcome of interest seems clear (increasing birth of a healthy baby), the approach can be more complicated; and as there is a de-linking of egg retrieval and ET, and as costs and procedures increase, we should be rigorous about our acceptance of change. This is not to stall change but to encourage the same rigor and questioning of accepted dogma expected in other fields of medicine. An approach based on standard clinical study design to allow appropriate comparisons between patients, and to allow the most comprehensive information for patient counseling, is presented.
Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California. Electronic address: Marcelle.cedars@ucsf.edu.
Marcelle I
MI
Cedars
D015925:Cryopreservation; D004624:Embryo Transfer / Q000009:adverse effects; D019317:Evidence-Based Medicine; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro / Q000009:adverse effects; D005820:Genetic Testing; D006801:Humans; D007246:Infertility / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D050498:Live Birth; D011247:Pregnancy; D018873:Pregnancy Rate; D019836:Preimplantation Diagnosis / Q000379:methods; D012107:Research Design; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
Day-5 embryo transfer; IVF; PGS; delayed embryo transfer; freeze all