Recent studies have shown that babies who are small for dates at birth, or who fail to grow in infancy, have, in adult life, raised blood pressure, impaired glucose tolerance, abnormal serum lipids, raised fibrinogen and high death rates from coronary disease, stroke and obstructive lung disease. This has led to the hypothesis that these diseases are ‘programmed’ in utero in response to an adverse environment.

Congenital diaphragmatic hernia (CDH) is a simple anatomical defect. The reported incidence is between 1:2000 and 1:5000 live births, with the majority affecting the left side. A defect in the diaphragm allows abdominal viscera to herniate into and stay within the thoracic cavity during crucial stages of lung development. This results in pulmonary hypoplasia, a reduction in pulmonary vascular branching and an alteration in the surfactant system.

The main function of the immune system is to protect the host from both pathogenic (ie. viruses, bacteria and foreign material) and neoplastic invasion. It is composed of both humoral and cellular factors. The humoral factors comprise the antibodies and the complement system, while the cellular factors comprise the lymphocytes and the phagocytes. These immunological factors remain in a relatively inactive state until activated by foreign molecules. Activation of the immune system under normal circumstances is beneficial to the host. In septic, multiply traumatized, critically ill surgical patients or severe preclamptic women, the host response to stress is more extensive and, as a result, extensive activation of immunological factors could create complications in the host like the adult respiratory distress syndrome (ARDS), multisystem organ failure (MOF) or the syndrome of haemolysis, elevated liver enzymes and low platelet count (HELLP) in preeclamptic women. In order to appreciate the later parts of this article regarding immunology and pregnancy, an understanding of the normal immune system is essential.

Prenatal diagnosis is one of the most rapidly expanding areas in medicine and now forms a significant part of Fetal Medicine subspecialization. With the introduction of new technologies in the areas of human genetics, fetal therapy and fetal pathology, those interested must work hard to keep abreast of the latest advances. General obstetricians and those involved in pregnancy counselling must now be aware of all diseases which can be transmitted and for which prenatal diagnosis and screening tests are available and appropriate. There is a plethora of reviews of current techniques and procedures and it would be repetitive for us to produce another such paper. Rather, this article aims to highlight those areas which by definition are changing and where we see future developments occurring. Those readers seeking in depth reviews of present methods are referred to standard texts.