Hematological complications of obstetrics, pregnancy and gynecology are many, and, unfortunately, often lead to significant morbidity or mortality for both mother and child, for example disseminated intravascular coagulation, amniotic fluid embolism or postoperative deep vein thrombosis/pulmonary embolus, not only in obstetrical patients but also common in postoperative gynecological patients – particularly those having surgery for a malignancy. These complications range from hemorrhagic complications, thrombotic complications, combinations (such as disseminated intravascular coagulation), various anemias, hemoglobinopathies and others. A textbook on this topic was last written in the 1970s, and for the past several decades, hematologists, obstetricians, gynecologists, reproductive medicine specialists, internists, anesthesiologists and others have had to rely upon research reports, small clinical trials, opinion, rare review articles and very brief chapters in obstetrical and gynecological textbooks. An additional problem is that busy specialists in the aforementioned areas have a difficult time keeping up with a logarithmic increase in medical information relative to their particular areas. Thus, we have compiled a textbook, written by experienced experts in the various aspects of hematological complications of obstetrics, pregnancy and gynecology to serve as a ready reference for practicing physicians in these specialties to quickly find information relative to these problems. In each instance, where appropriate, the etiology, pathophysiology, clinical and laboratory diagnosis and management are discussed. It is hoped this text will help the practicing specialists caring for women with these hematological complications of pregnancy and the end result will be improved understanding, improved diagnosis, improved principles of management, and enhanced morbidity and mortality for these too often catastrophic problems.