Advantages of the two-step embryo transfer strategy in human IVF/ICSI cycles.
The aim of this study was to evaluate the advantages of the two-step embryo transfer (ET) strategy combining a day 2/3 ET with a day 5/6 blastocyst transfer. In an observational comparative study, 400 infertile women were enrolled from two assisted reproductive technology (ART) units according to inclusion criteria: age below 42 years and at least three embryos obtained on day 2 thus allowing an extended in vitro culture. Two groups were defined according to the ET strategy adopted: group 1 had a two-step ET; and group 2 had a day 2/3 ET with (subgroup 2a) or without (subgroup 2b) blastocysts cryopreserved on day 5/6. Live birth rate was significantly higher in group 1 than in subgroups 2a and 2b (36.5% versus 29.4% and 13.4%, respectively; p < 10(-3)). Multiple pregnancy rates were comparable between groups. After adjusting on major prognostic factors, the two-step ET strategy was still associated with a significantly higher live birth rate than the day 2/3 ET (OR = 2.23; 95% CI: 1.32-3.77). The two-step ET provides better live birth rates than the cleavage-stage ET. It does not increase multiple pregnancy rates if the number of embryos transferred is limited. It also prevents cycle loss when embryos fail to develop into blastocysts.
Service de Gynécologie Obstétrique, Hôpital Bichat Claude Bernard, 46 rue Henri Huchard, 75018 Paris, France. chayazmd@hotmail.com
Chadi
C
Yazbeck
Nadia
N
Ben Jamaa
André
A
Hazout
Paul
P
Cohen-Bacrie
Anne-Marie
AM
Junca
Nathalie
N
Rougier
D000328:Adult; D001755:Blastocyst / Q000502:physiology; D015925:Cryopreservation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D050498:Live Birth / Q000453:epidemiology; D010062:Ovulation Induction; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D020554:Sperm Injections, Intracytoplasmic