When an antenatal diagnosis of a fetal anomaly is made, the parents need accurate and clear information regarding prognosis and possible outcomes, to help them make decisions. The healthcare professionals, who are involved in their care and counselling, also need this information.

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.

The most important congenital heart disorders occurring in children are mainly due to malformations of cardiac structure. The underlying anatomical defect is established soon after the heart is first formed in embryonic life, less than 8 weeks after conception. However, the full echocardiographic picture may not be apparent until after birth or even later in childhood.

The optimal mode of breech delivery has been one of the major controversies in Obstetrics, until the Term Breech Trial was published in 2000. This multi-centre randomised trial showed that planned Caesarean breech delivery is safer than planned vaginal breech delivery, resulting in a significant reduction in perinatal death and serious neonatal morbidity by two-thirds. Since then there was a rapid and significant worldwide changes in the clinical management of breech presentation at term towards planned Caesarean section (CS). Although the Term Breech Trial is a well-designed and conducted study, it is not without criticism. Firstly, among the perinatal deaths reported in the study, some were unrelated to the mode of delivery such as antenatal stillbirths. If such perinatal losses were excluded from analysis, the difference in perinatal death might not have reach statistical significance. Secondly, some intrapartum deaths occurred during intermittent fetal heart monitoring. It is plausible that these could have been prevented if continuous monitoring had had carried out. Furthermore, although neonatal morbidity after vaginal breech delivery is higher, whether these morbidities have significant long term developmental or neurological effect is still controversial. In fact in the follow-up study of babies from the Term Breech trial at the age of 2 years, no statistically significant difference in neurodevelopmental delay or death rate was found in children between the treatment groups. Finally, the cost for the preventing 1 perinatal death or serious fetal morbidity requires an additional performance of 14 CSs. This figure rises to 39 CSs among developing countries. Elective CS is not only associated with an increase in short-term maternal morbidity, but also long term complications including risk of scar rupture in subsequent pregnancies, placenta praevia, abnormal adherent placentation, and of unexplained antenatal stillbirth. The medical cost for managing these long term complications could be substantial.

The fetus has become increasingly accessible and visible as a patient over the last two decades. Two major technical advances have contributed to the obstetrician's ability to study and understand the fetus. The first advance was electronic fetal heart-rate monitoring, followed by the second major advancement in the form of real time ultrasound. Prior to the introduction of these technologies, biochemical determiniations of oestriol and human placental lactogen were used to monitor fetal wellbeing. Currently the emphasis, both in clinical practice and research protocols, is on biophysical surveillance of the fetus.

Pregnancy is a physiological condition that affects all organs. Diseases unrelated to pregnancy may present coincidentally during pregnancy or may be exacerbated by pregnancy, and may increase maternal and/or fetal morbidity or mortality. Compared with many other systems, the changes within the biliary tree and pancreas are relatively minimal. However, pregnancy is associated with an increased likelihood of cholelithiasis, which can have significant implications for the parturient.

Hypoplastic Left Heart Syndrome (HLHS) was first described fifty years ago. It is characterised by underdevelopment of the left ventricle with associated aortic and mitral valve hypoplasia or atresia, and varying degrees of hypoplasia of the aortic arch (Figure 1). In utero a physiological right to left shunt of oxygenated blood through the ductus arteriosus bypasses the obstruction and allows normal fetal growth. Closure of the ductus arteriosus in the post-natal period interrupts systemic blood flow, resulting in rapid deterioration and death. Untreated it is a universally fatal condition, leading to neonatal death within the first few days or weeks of life. Although HLHS affects only one baby in 10,000 and accounts for less than 10% of all congenital heart disease, HLHS is responsible for 25% of all deaths due to congenital cardiac disease occurring within the first week of life.

Adolescent pregnancy rates in the United Kingdom remain the highest in Western Europe. Interestingly, throughout most of Western Europe teenage birth rates fell during the 1970s, 80s and 90s, but in the United Kingdom rates have remained high. An increasing incidence has also been noted, with 49.9 births per 1,000 women under 18 in 2001 and 52.8 live births per 1,000 women in 2002.

Efficient respiration in a baby relies on adequate anatomical development of the lungs, effective control of respiration, neuromuscular coordination and anatomical and biochemical maturation of the alveoli so that they are stable, thin-walled and in close proximity to the alveolar capillary bed. As well as maturation of lung function, there must also be a major change in pulmonary blood flow at birth to allow perfusion of the capillary bed with deoxygenated blood in order that effective gas exchange can take place. Successful initiation and sustaining of repiration after birth requires all of these things to occur simultaneously otherwise respiratory failure will ensue.

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.

In the modern Health Service frequent inspection has become commonplace. These inspections are often viewed with a degree of suspicion by clinicians and none has fallen into greater disrepute than the visits conducted for the Clinical Negligence Scheme for Trusts, CNST. These visits are often seen as a ‘Tick box’ exercise, more important to the finances of the Trust than the care of patients. Fortunately as with many other generalisations this is incorrect. Although one can always disagree with individual standards examined during this inspection the fundamental principles that these standards are based upon are often suggested by medical colleges and are founded on sound risk management theory.

Shoulder dystocia is an unpredictable obstetrical emergency that results in serious complications especially to the neonate. Such complications include fracture of the clavicle, brachial plexus injury, fracture of the humerus and asphyxia.1-4 The incidence of shoulder dystocia appears to be increasing5 and its unpredictability continues to be the nightmare of the obstetrician. The following is a review of risk factors which are associated with shoulder dystocia, a critical review of the usefulness of antenatal ultrasound in the prediction of the macrosomic fetus and a discussion of the controversies surrounding the management of shoulder dystocia.

Gestational diabetes mellitus (GDM) is defined as ‘carbohydrate intolerance of variable severity with onset or first recognition during pregnancy’. GDM affects approximately 4–10% of all pregnancies in the United States. Pregnancies complicated by GDM have both short and long term effects on the developing fetus. Studies have shown that elevated levels of glycaemia are associated with increased perinatal mortality. O'Sullivan et al. in his original work, found a four-fold higher rate of perinatal mortality in untreated women with gestational diabetes when compared to women with a normal glucose tolerance test in the same time period. Pettit et al., when studying Pima Indians, found a direct association between a 2-hour, 75g glucose load result and perinatal mortality. Evaluation of recent studies concerning gestational diabetes revealed relatively high rates of stillbirth and perinatal mortality. Thus, it is clear that lack of a therapeutic regimen for these patients will result in increased fetal mortality.

The antiphospholipid (aPL) syndrome has been defined as the production of autoantibodies against negatively charged phospholipids or phospholipid-protein complexes, clinically associated with thrombocytopenia, thrombosis, or pregnancy loss. The syndrome is considered a disease of systemic thrombosis. The frequency of thrombosis, however, is very low, despite most patients having stable levels of circulating aPLs. Documented thrombosis occurs only in approximately 35% of the patients, and, if recurrent, the events are generally separated by years (Table 1). The most common complication, however, is disturbance of pregnancy. Patients with aPLs have an 80% to 90% pregnancy loss rate, half of which occur in the first trimester. The incidence of pregnancy loss, however, depends on the criteria upon which the patients were selected and whether pregnancy outcome is analyzed retrospectively or prospectively. In some studies the pregnancy loss rate may be as low as 50% to 75%. Even the few cases of successful pregnancy are at risk of intrauterine growth restriction (IUGR), placental abruption, prematurity, and early and severe pregnancy-induced hypertension (PIH). Therefore, the vast majority of pregnancies in the presence of aPLs result in miscarriage or are severely complicated, with indications that placental damage occurs by the first trimester. When pregnancies are evaluated in the first trimester by ultrasound, IUGR is observed commonly before the death of the fetus. The strong and relatively specific association with pregnancy complications suggests that the syndrome should be redefined as “a syndrome of pregnancy”.

Preterm birth is a significant contributor to perinatal morbidity and mortality. Any intervention to effectively decrease the complications of a preterm birth must not only delay or prevent preterm delivery, but also improve neonatal outcomes. Until recently, interventions to prevent preterm birth have been largely unsuccessful. While some interventions are demonstrated to delay delivery for a short interval, the increased latency period does not result in improved neonatal outcomes. Recently, two randomized clinical trials demonstrated that progestational agents may decrease the incidence of preterm birth. As obstetricians, it is critical that we question the biological plausibility of a treatment prior to using it as standard of care. This review will address the physiologic role of progesterone in preterm and term labour, the molecular mechanisms by which progestational agents might exert a biological effect and the possible mechanisms by which these agents may prevent preterm birth.

Preterm delivery occurs in less than 10% of pregnancies but accounts for more than 70% of all neonatal deaths. Approximately one third of preterm deliveries are associated with preterm prelabour amniorrhexis. In those with infection, labour frequently ensues and survival depends on gestational age at amniorrhexis. In those without infection the pregnancy continues and death is then dependent on the development of pulmonary hypoplasia (PH).

Almost 80 years ago George Corner and colleagues provided the first evidence that progesterone maintains pregnancy and that it does so, at least in part, by promoting myometrial relaxation. In the 1950s, Arpad Csapo proposed the “progesterone block hypothesis”, which posits that progesterone maintains pregnancy by promoting myometrial relaxation and that its withdrawal initiates a cascade of hormonal interactions that transforms the myometrium to a highly contractile state leading to the onset of labour. Csapo later proposed that contractility of the pregnant myometrium is determined by the balance between relaxation induced by progesterone and contraction induced by a cohort of signals including oestrogens, uterine distention and stimulatory uterotonins such as prostaglandins (PGs) and oxytocin (OT). According to this “seesaw” hypothesis, progesterone promotes myometrial relaxation by directly inducing relaxation and/or by inhibiting the production of, or myometrial responsiveness to, stimulatory uterotonins. These landmark concepts, though derived from studies of experimental animals, form the foundation for current understanding of progesterone's role in the physiology of human pregnancy. Remarkable progress has been made over the last 20–30 years in understanding the signal transduction pathways through which steroid hormones affect target cells. This knowledge has broadened the scope of Csapo's original paradigms and we are now beginning to unravel the specific signaling pathways and molecular interactions by which progesterone affects human myometrium and how its actions are controlled at the functional level. This is important for the development of progestin-based therapeutics for the prevention or suppression of preterm labour and preterm birth. Here we review recent progress in understanding the mechanisms by which progesterone sustains pregnancy and in particular how it promotes myometrial relaxation, how its relaxatory actions are nullified at parturition, and the hormonal interactions that induce progesterone withdrawal to determine the timing of human birth.

In the Obstetrical Journal of Great Britain and Ireland (August 1878), Dr Hamilton from Falkirk, Scotland wrote an article entitled “mortality in childbed statistics”. Quoting a Dr Murphy, he stated that “in 75,911 cases of midwifery occurring in British practice, there were 138 forceps cases, and in thirty five of these, or one in every four, the child was stillborn”. Then, as now, obstetricians were discussing intervention during labour and were divided in their views, with one side claiming that intervention caused fetal loss, while the other side being convinced that only by intervention would lives of mothers and babies be saved.

The efficacy of labour is determined by uterine, fetopelvic and cervical factors. Whereas the first two of these are well recognized, acknowledgement of the modulating function of the cervix during labour is relatively new. In particular, clarification of the synthesis and metabolism of prostaglandins has contributed considerably to our understanding of the biological control of the cervix.