With new information available, authors of a Cochrane Systematic Review have revised their conclusions about the relative effectiveness of two treatments used to help women be­come pregnant. They now conclude that giving women gonadotrophin-releasing hormone (GnRH) antagonists leads to similar live-birth rates compared with GnRH agonists. Previously they had concluded that women who used antagonists tended to have lower birth rates than those using agonists. 

The systematic review also show­ed that GnRH antagonists can halve the risk of over-stimulating the ovaries compared with GnRH agonists, as well as halving the number of women who have to pull out of a cycle of therapy. 

In 2006, when the researchers reach­­ed their earlier conclusion, they were only able to draw data from 27 trials. Since then more research has been published, allowing them to consider the findings of 45 randomised controlled studies that involved a total of 7511 women. 

More information is available at www.thecochranelibrary.com [8].