05 March 2012
By Linda Wijlaars
Appeared in BioNews 647
Protecting embryos from a laboratory environment during IVF treatment could increase successful pregnancy rates from 35 percent to 45 percent. A novel system, trialled in a recent study, consists of a chain of fully enclosed, interlinked incubators, provides a tightly controlled and protected environment.
‘Our aim was to keep eggs and embryos in conditions similar to those they would experience naturally – inside a woman’s body. This led our team to design and develop a system in which it is possible to perform all of the technical procedures while maintaining stable conditions throughout the IVF process‘, said Professor Mary Herbert, who led the research team at Newcastle Fertility Centre at Life, part of Newcastle Hospitals NHS Foundation Trust.
The system that is currently used in most IVF labs requires embryos to be removed from their incubators to check their development. During the short time they are out of their protective environment, temperature fluctuations and slight disturbances in the acidity, or pH balance, could influence the embryo’s development.
The team used mouse embryos to test whether the new system resulted in a more controlled environment for embryos. They found that both temperature and pH levels were significantly more stable in the new system compared to the conventional system. When using human embryos they found that blastocysts, an early stage of an embryo, developed faster and contained more cells than embryos grown in the conventional system.
Finally, the team measured how many women became clinically pregnant (a fetal heartbeat at seven weeks) when the fertility clinic used either the conventional IVF system or the new, fully enclosed system. While rates were between 32 and 35 percent with conventional systems, 45 percent of women became clinically pregnant with the new system. The women, who were 37 years or younger, had had ten egg follicles harvested and were all undergoing their first treatment cycle.
Although the increase in successful pregnancies looks promising, the researchers warn that causes other than the new system could have improved success rates. For instance, the team could have become gradually better at performing the IVF process over time. However, the study, published in PLoS ONE, tried to take this into account and still concluded that the improved pregnancy outcomes were due to the beneficial effects of the new system.
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