Should we advise patients undergoing IVF to start a cycle leading to a day 3 or a day 5 transfer?
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.
Centre for Reproductive Medicine, Dutch-Speaking Brussels Free University, Laarbeeklaan 101, 1090 Brussels, Belgium. stratis@easynet.be
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Kolibianakis
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Zikopoulos
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Verpoest
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Camus
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Joris
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Van Steirteghem
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Devroey
D000328:Adult; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D015925:Cryopreservation; D046149:Embryo Culture Techniques; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D005640:Follicle Stimulating Hormone / Q000627:therapeutic use; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists / Q000037:antagonists & inhibitors; D006801:Humans; D007247:Infertility, Female / Q000209:etiology / Q000628:therapy; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D013997:Time Factors
D007987:Gonadotropin-Releasing Hormone; D005640:Follicle Stimulating Hormone