This book explains how the immune system can behave in a way that prevents a pregnancy from continuing. High levels of Natural Killer cells, genetic compatibility between partners and blood clotting problems are all significant causes of reproductive failure. Autoimmunity (both inherited or environmentally triggered) are a major reason for the increase in infertility and miscarriage today. This book also explains why such disorders are not just devastating to a pregnancy and can also be markers of potentially serious health problems in the mother. This text includes contributions from Professor David Clark, Dr Carolyn Coulam, Dr William Matzner and Dr Geoffrey Sher.