The introduction of in vitro fertilization into fertility practice revolutionized the field of Reproductive
Medicine, invigorating its emergence as a new subspecialty distinct from, but associated with, Obstetrics or Gynaecology. Over the past 20 years we have observed increasing divergence of these subspecialties.
However, increasing recognition that periconceptional events determine not only fertility, but also
pregnancy outcome and the long term health of mother and offspring, is causing a reverse in this trend.
As perinatologists acknowledge that the outcome of pregnancy is largely determined during the periconceptional period, their focus is increasingly turning to optimizing early pregnancy and preconceptional health. At the same time, the improved prognosis associated with illnesses such as cystic fibrosis mean that many chronically ill women are now achieving reproductive age and wishing to have children. In addition, the increasing age of women presenting for fertility treatment is placing new demands on reproductive endocrinologists to ensure safe and effective treatment of the subfertile couple and the establishment of a healthy pregnancy. Reproductive endocrinologists are now taking responsibility for optimizing preconceptional conditions in their patients and are working closely with perinatologists and other disciplines to ensure that optimal pregnancy outcomes are achieved. At this interface between Reproductive Medicine, Perinatology, Internal Medicine and Genetics, the new field of Periconceptional Medicine is emerging. As three clinicians approaching this area from the different perspectives of Reproductive Medicine and Perinatology, we recognized the need for a single integrated and authoritative textbook to provide a theoretical and clinical basis to this new field of medicine. In drawing together the different strands of knowledge into a single text, we have been fortunate to engage the services of diverse leading authorities from around the world. We hope that the result of their efforts will provide a sound theoretical basis for those practising in this new and exciting field of Periconceptional Medicine.