Despite many advances in the management of lung disorders of premature infants, respiratory distress syndrome (RDS) remains the major cause of morbidity and mortality in the preterm infant. Approximately 30% of infants born at less than 34 weeks gestation will develop RDS, secondary to deficiency in surfactant production by alveolar type II pneumocytes. Without surfactant, work of breathing is increased and gas exchange impaired by diffuse atelectasis, reduced pulmonary compliance and ventilation perfusion mismatch.

Definitions of domestic violence vary according to the frequency, severity and nature of the violence as well as the context in which it occurred and the relationship between the victim and the perpetrator. Though there is a lack of uniformity, a generally accepted definition of domestic violence is the physical, sexual or emotional abuse of an adult woman by a man with whom she has or has had an intimate relationship, regardless of whether the couple are living together. Although violence can be carried out by other family members or occur in same-sex relationships, it is argued that men use violence in order to maintain dominance and control over their female partners. Physical violence is just one of the many tactics that an abuser may use to exert control over his partner. Other behaviours include isolation, intimidation, threats of violence, threats to take the children away or hurt them and emotional or economic abuse. Whilst some studies have identified demographic patterns associated with domestic violence, it can affect any woman regardless of age, race, ethnicity, social class, employment status, religion, marital status or disability.

Oxygen radicals and reactive oxygen species are normal attributes of aerobic life. In most molecules, the electrons are paired and, with the exception of hydrogen, the four outer most pairs of each atom form chemical bonds. Electrons are in a relatively stable energy state when paired. A free radical is a molecule with an unpaired electron. Free radicals of oxygen are of particular importance to living organisms in which they are involved in the genesis of a wide array of diseases and physiological processes (e.g. life span and ageing).

Because half its genes are inherited from the father, the embryo during pregnancy has been frequently compared to an allograft transplanted into the maternal uterus. The question why the embryo is, therefore, not rejected by the mother's immune response in the same way as other allografts has still not been satisfactorily answered. Recent investigations indicate that this analogy may not be as close as it initially appears. One major difference is the expression of an unusual combination of HLA class I molecules by the placental trophoblast cells which invade into uterine decidua during implantation. Furthermore, the lymphoid population in the uterus potentially capable of interacting with these trophoblast HLA class I antigens also appears to be unique. These observations have led to the suggestion that implantation might utilise a novel immune system which is different to that seen in clinical transplantation immunology. Much research effort is now directed towards the elucidation of the mechanisms involved and the outcome of this interaction because this is likely to be how implantation is controlled.