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20-06-2010 | Gynaecology | Article

Fresh blastocyst transfer results in ‘healthiest’ babies


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MedWire News: To maximize the chances of having a healthy baby after assisted reproductive technology, embryos should be transferred to the uterus as fresh blastocysts, report Australian researchers.

Transferring fresh blastocysts resulted in more babies born at term weighing 2500 g or more and surviving for at least 28 days, compared with transferring blastocysts cultured from thawed cleavage embryos, thawed blastocysts, or thawed cleavage embryos, say Yueping Alex Wang from the University of New South Wales in Randwick, and colleagues.

The team examined live delivery rates and numbers of healthy babies (according to the above definition) in 150,376 embryo transfer cycles.

Live delivery rates were significantly higher for fresh blastocyst transfers than for blastocysts cultured from thawed cleavage embryos, fresh cleavage embryo transfers, thawed blastocysts, and thawed cleavage embryos at 27.9 percent versus 22.0, 21.7, 16.3, and 15.2 percent, respectively.

Furthermore, when compared with fresh blastocysts, blastocysts cultured from thawed cleavage embryos were 27 percent less likely to be healthy, fresh cleavage embryos were 33 percent less likely, thawed blastocysts were 43 percent less likely, and thawed cleavage embryos were 47 percent less likely to be healthy.

A clinical practice model which followed this pattern for embryo transfer would be the optimum model, suggest Wang and team.

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Sarah Guy