Related Experiment Video
Updated: Aug 23, 2026
Fertility Preservation Through Oocyte Vitrification: Clinical and Laboratory Perspectives
Published on: September 16, 2021
Should we advise patients undergoing IVF to start a cycle leading to a day 3 or a day 5 transfer?
E M Kolibianakis1, K Zikopoulos, W Verpoest
1Centre for Reproductive Medicine, Dutch-Speaking Brussels Free University, Laarbeeklaan 101, 1090 Brussels, Belgium. stratis@easynet.be
Background:
The aim of this study was to compare ongoing pregnancy rates per started cycle between patients randomized at consultation to have embryo transfer either on day 3 or on day 5 of in-vitro culture.
Methods:
All patients <43 years of age for whom IVF was indicated were allowed to participate in the study (day 3 group, 234 patients; day 5 group, 226 patients). Ovarian stimulation was performed either using GnRH antagonists/recombinant FSH (rFSH) (day 3, 70.1% of patients; day 5, 72.6% of patients) or using the long GnRH agonist protocol/urinary gonadotropins (day 3, 29.9% of patients; day 5 27.4% of patients).
Results:
The random decision to initiate a cycle leading to day 5 as compared with a day 3 transfer was associated with a significantly lower chance of embryo cryopreservation (day 3, 61.5%; day 5, 50.4%; P<0.02). Ongoing pregnancy rate per started cycle did not differ between the two groups compared [day 3, 32.1%, 95% confidence interval (CI) 26.4-38.2%; day 5, 33.2%, 95% CI 27.3-39.5%].
Conclusions:
Advising patients at consultation to initiate an IVF cycle leading to a day 5 as compared with a day 3 transfer does not appear to increase the probability of ongoing pregnancy, and is associated with a significantly lower probability of obtaining cryopreserved embryos.
