Narrator: This is Science Today. The process of a week-old human embryo to implant itself to the uterine wall, called implantation, has been discovered by researchers at the University of California, San Francisco. Dr. Susan Fisher, who led the study, says defects in this early process may be the main problem for about two million American women with unexplained infertility.
Fisher: Human implantation has always been very much a black box and it's really important to know what's inside that black box because human reproduction is a very inefficient process - I think most people don't realize how inefficient it is.
Narrator: Even at peak fertility, a woman in a given month has only about a 30 percent chance to get pregnant.
Fisher: We know that infertility now in our society has really reached epidemic proportions, so it's really important to understand the components of implantation and early establishment of pregnancy.
Narrator: For Science Today, I'm Larissa Branin.