Embryo Culture and Development

Some of the most important events in the IVF treatment cycle now occur behind the scenes, in our laboratory. Our security in handling eggs, sperm and embryos is unusually meticulous. Our laboratory protocol, SurTransferSM (see detailed article in Additional Information section) calls for two of our board certified embryologists to be present at all critical steps to avoid any potential errors.  

The eggs mature for several hours in culture media. This media is made up of essential amino acids and other components necessary for good embryo development. The nutrients and sperm are then added to the eggs and media, usually in the afternoon of the egg retrieval. The addition of sperm to the culture media is called insemination. Insemination is followed several hours later by fertilization, when the sperm enters the egg. 

The stages that follow are very important to the future embryo. After fertilization, the sperm loses its tail and its head enlarges, so that, at this stage, the egg looks like a cell with two nuclei, called pro-nuclei. The pro-nuclei, which individually hold the genetic material of the sperm and the egg, are called pro-nuclei because each has only half the DNA of a normal nucleus. You may hear this stage referred to as the two pro-nuclear or 2PN stage.  Identification of the 2PN stage is very important to determine if fertilization has occurred.