Single-embryo transfer maintains birth rate, reduces multipl
Verfasst: 04 Dez 2004 17:42
Single-embryo transfer maintains birth rate, reduces multiple gestation risk
Last Updated: 2004-12-01
NEW YORK (Reuters Health) - Transfer of a single embryo during in vitro fertilization (IVF) reduces the risk of multiple births but does not substantially lower the rate of live births compared with the transfer of two fresh embryos simultaneously, Scandinavian physicians report in the December 2nd issue of The New England Journal of Medicine.
Multifetal pregnancies are associated with an increased risk of adverse clinical outcomes, senior author Dr. Christina Bergh and colleagues explain, and those that occur after IVF are due primarily to the transfer of multiple embryos at a time. Their goal was to reduce this risk by transferring only a single embryo at a time.
Dr. Bergh, of the Sahlgrenska University Hospital in Goteborg, Sweden, and her associates enrolled 661 patients age 35 or younger undergoing their first or second IVF cycle, who had at least two embryos of good quality.
They randomly assigned 331 patients to undergo double-embryo transfer and 330 to undergo transfer of a single fresh embryo and, if there was no live birth, subsequent transfer of a single frozen and thawed embryo.
Rates of multiple births were 33.1% in the double-embryo-transfer group versus 0.8% in the single-embryo-transfer group (p < 0.001). Pregnancy resulting in at least one live birth occurred in 42.9% and in 38.8%, respectively.
"Disadvantages of single-embryo transfer, such as inconvenience and the stress of an additional cycle... must be balanced against the much higher risk of multiple gestation with double-embryo transfer," the authors write.
"This intriguing study underscores the need to monitor trends in the outcomes of in vitro fertilization, to develop techniques to identify and select embryos with the highest potential for implantation, and to optimize protocols for embryo cryopreservation so as to reduce embryo loss and narrow the gap in pregnancy rates between transfers of fresh and thawed embryos," Dr. Owen K. Davis, of Weill Medical College of Cornell University in New York, comments in a related editorial.
Source : N Engl J Med 2004;351:2392-2402,2440-2442.
Last Updated: 2004-12-01
NEW YORK (Reuters Health) - Transfer of a single embryo during in vitro fertilization (IVF) reduces the risk of multiple births but does not substantially lower the rate of live births compared with the transfer of two fresh embryos simultaneously, Scandinavian physicians report in the December 2nd issue of The New England Journal of Medicine.
Multifetal pregnancies are associated with an increased risk of adverse clinical outcomes, senior author Dr. Christina Bergh and colleagues explain, and those that occur after IVF are due primarily to the transfer of multiple embryos at a time. Their goal was to reduce this risk by transferring only a single embryo at a time.
Dr. Bergh, of the Sahlgrenska University Hospital in Goteborg, Sweden, and her associates enrolled 661 patients age 35 or younger undergoing their first or second IVF cycle, who had at least two embryos of good quality.
They randomly assigned 331 patients to undergo double-embryo transfer and 330 to undergo transfer of a single fresh embryo and, if there was no live birth, subsequent transfer of a single frozen and thawed embryo.
Rates of multiple births were 33.1% in the double-embryo-transfer group versus 0.8% in the single-embryo-transfer group (p < 0.001). Pregnancy resulting in at least one live birth occurred in 42.9% and in 38.8%, respectively.
"Disadvantages of single-embryo transfer, such as inconvenience and the stress of an additional cycle... must be balanced against the much higher risk of multiple gestation with double-embryo transfer," the authors write.
"This intriguing study underscores the need to monitor trends in the outcomes of in vitro fertilization, to develop techniques to identify and select embryos with the highest potential for implantation, and to optimize protocols for embryo cryopreservation so as to reduce embryo loss and narrow the gap in pregnancy rates between transfers of fresh and thawed embryos," Dr. Owen K. Davis, of Weill Medical College of Cornell University in New York, comments in a related editorial.
Source : N Engl J Med 2004;351:2392-2402,2440-2442.