Objective: Blastocysts are reportedly suitable for preventing multiple pregnancies as a result of the high implantation rate per embryo. The present study compared clinical results for elective single embryo transfer (ET) between blastocysts and cleavage-stage embryos in order to ascertain the usefulness of blastocyst culturing in single ET. Methods: Between January 2002 and December 2004, conventional in vitro fertilization ET and/or intracytoplasmic sperm injection was carried out for single ET in 86 cycles, to prevent multiple pregnancies (for medical reasons or because of patient wishes). Results: Among the 80 cycles in which a fresh embryo was transferred, pregnancy/implantation rates per ET were 35.3% for day 2/3 ET and 50.0% for day 5 ET, and pregnancy/implantation rates per oocyte retrieval were 35.3% for day 2/3 ET and 44.2% for day 5 ET. Ongoing pregnancy/delivery rates per oocyte retrieval were 32.4% for day 2/3 ET and 38.5% for day 5 ET. Monozygotic twinning occurred in one case of day 5 ET. Conclusions: Pregnancy rates per single ET tended to be higher for day 5 ET than for day 2/3 ET. However, no marked differences were identified in ongoing pregnancy/delivery rates per oocyte retrieval between groups. (Reprod Med Biol 2005; 4: 197-201).
Objective: Blastocysts are reportedly suitable for preventing multiple pregnancies as a result of the high implantation rate per embryo. The present study compared clinical results for elective single embryo transfer (ET) between blastocysts and cleavage-stage embryos in order to ascertain the usefulness of blastocyst culturing in single ET. Methods: Between January 2002 and December 2004, conventional in vitro fertilization ET and/or intracytoplasmic sperm injection was carried out for single ET in 86 cycles, to prevent multiple pregnancies (for medical reasons or because of patient wishes). Results: Among the 80 cycles in which a fresh embryo was transferred, pregnancy/implantation rates per ET were 35.3% for day 2/3 ET and 50.0% for day 5 ET, and pregnancy/implantation rates per oocyte retrieval were 35.3% for day 2/3 ET and 44.2% for day 5 ET. Ongoing pregnancy/delivery rates per oocyte retrieval were 32.4% for day 2/3 ET and 38.5% for day 5 ET. Monozygotic twinning occurred in one case of day 5 ET. Conclusions: Pregnancy rates per single ET tended to be higher for day 5 ET than for day 2/3 ET. However, no marked differences were identified in ongoing pregnancy/delivery rates per oocyte retrieval between groups. (Reprod Med Biol 2005; 4: 197-201).
Entities:
Keywords:
blastocyst transfer; cleavage‐stage embryo transfer; single embryo transfer
Authors: E M Kolibianakis; K Zikopoulos; W Verpoest; M Camus; H Joris; A C Van Steirteghem; P Devroey Journal: Hum Reprod Date: 2004-08-06 Impact factor: 6.918