Top quality embryos at day 2: a prerequisite for single blastocyst transfer? An observational cohort study in women under 36.
OBJECTIVE
While extended culture has been considerably improved, some questions remain regarding the application of Single Blastocyst Transfer (SBT).


METHODS
An observational cohort study was undertaken with 456 women under 36 years old and assigned to SBT on a voluntary basis. The main outcome was the cumulative delivery rate per couple according to the number of Top Quality Embryos (TQE) on day 2 (Group 1= > or =2 TQE, Group 2= 1 TQE and Group 3= 0 TQE).


RESULTS
Rate of transfer and mean number of frozen blastocyts were higher in Group 1 compared to Group 3. As a consequence, the cumulative delivery rate per couple was higher in Group 1 (47.9%) compared to Group 3 (34.9%).


CONCLUSIONS
Single blastocyst transfer combining fresh and frozen cycles, might be a worthwhile strategy irrespective of embryo quality on day 2 providing good delivery rates while keeping the rate of multiple deliveries low.
Guerif
Fabrice
F
Service de Médecine et Biologie de la Reproduction, CHRU Bretonneau, 37000, Tours, France. guerif@med.univ-tours.fr
Lemseffer
Malak
M
Blanchard
Milène
M
Royere
Dominique
D
D000328:Adult; D000367:Age Factors; D001755:Blastocyst / Q000502:physiology; D015331:Cohort Studies; D046149:Embryo Culture Techniques; D004624:Embryo Transfer / Q000379:methods*; D004622:Embryo, Mammalian / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D013997:Time Factors