National Toxicology Program

The human body has a complex system of defense mechanisms that are designed to protect against substances it deems to be foreign to itself.   Unfortunately, complications can occur with pregnancy if the woman's immune system treats the fetus or sperm as foreign.  Women with recurrent pregnancy loss may be suffering from one of five different types of complications with immunologic factors.   The following topics link to web pages that contain more detailed information. 

• General Information on Category 1 to 5 Immunologic Disorders
• Rh Factor