New In Vitro System Increases Success Rate.

• Position: Brief Article

A revolutionary culturing method for the in vitro development of embryos known as the blastocyst culture system enables physicians at Yale-New Haven (Conn.) Hospital to achieve pregnancy rates in excess of 50%. The mean in vitro pregnancy rate in the U.S. among those facilities that utilize the standard "random selection" method is roughly 25%.

Ervin Jones, professor and director of assisted reproduction, explains that standard in vitro culture systems--consisting of sugars, salts, and ions--only allow two- to three-day development, resulting in four- to eight-cell embryos. "The old culture isn't adequate for sustaining cell growth after that stage, and the embryos have to be transferred to the uterus...