Although significant advances to patient care have been made in various branches of obstetrics and gynaecology, the incidence of preterm birth has not changed in the past 40 years. Indeed there are signs that factors such as low socioeconomic status of some inner city populations, the tendency for women to choose to start a family at an older age and the impact of fertility treatments are leading to an increase in the incidence of preterm delivery. Improved neonatal care over this period has significantly reduced the mortality rate due to prematurity, although it remains the primary cause of neonatal death. The morbidity rate in preterm infants, however, has not substantially changed due largely to the resuscitation of neonates at or close to the limits of gestational age viability. This has inevitably had a tremendous economic impact upon health care systems and upon society in general. Neonatal care in the USA alone cost over $5 billion annually in the 1980s – the vast majority of which was due to prematurity. When one adds the costs of chronic care for some of these infants with major motor and/or mental handicaps as well as the loss of potential earnings, prematurity ranks as one of the most costly of medical complications.

Group B streptococcal disease is the commonest cause of early-onset neonatal sepsis in most developed countries. Recent epidemiological studies and controlled trials have shown that many cases are theoretically preventable and guidelines have been widely adopted in the United States and Australia but are not common place in much of Europe. Infections caused by group B streptococcus may present at any time before, during or after delivery. This article reviews aspects of early-onset sepsis in the newborn infant (clinical presentation in the first 48 hours) as almost all of these cases are maternally acquired. Microbiological, epidemiological, pathophysiological and clinical aspects of the disease are discussed, and the practical implications of adopting preventative programmes are addressed.

Advances in both imaging techniques and in treatments for immune thrombocytopenias affecting the fetus have allowed for more accurate antenatal predictions of severe disease and effective antenatal treatments for those fetuses who are at risk of sequelae. This article will review current knowledge of the diagnosis and treatment of affected fetuses in alloimmune thrombocytopenia and in immune thrombocytopenic purpura.

Prelabour rupture of the membranes(PROM) is generally defined as rupture of the membranes prior to the onset of labour. When this occurs at term (greather than/equal 37 weeks of pregnancy) it is referred to as term PROM (to distinguish it from preterm PROM). The time interval between membrane rupture and the onset of labour is termed the latent period. The duration of this period is known to vary inversely with the gestational age at membrane rupture.

The hypertensive disorders of pregnancy remain a significant problem in antenatal care. The measurement of blood pressure in pregnancy is fundamental in diagnosing and managing these conditions. The introduction of technology in the form of ambulatory automated blood pressure monitors has allowed multiple, standardised measurements to be made away from the clinical environment, and has addressed many of the errors associated with conventional sphygmomanometry. This article explores the potential role of ambulatory blood pressure monitoring in pregnancy.

The adhesion of cells to each other, to other cell types and to the extracellular matrix (ECM) is a crucial part of development and relies on the expression of cell adhesion molecules (CAMs) and their ligands. For example, at implantation, the trophoectoderm attaches to the uterine epithelial surface and CAMs play a major role in this process. Following attachment, interstitial and intravascular invasion of maternal tissue by trophoblast is required to develop the maternal-placental-fetal circulation and this too requires a new repertoire of CAM expression. Understanding the part played by adhesion molecules in pregnancy is paramount because several pregnancy associated disorders including pre-eclampsia, fetal growth retardation, miscarriage and infertility problems have been linked to abnormalities in expression of particular CAMs and/or their ligands. The aim of this article is to review the major CAM families and their role in human pregnancy. Excellent reviews which include reference to animal studies can be found elsewhere.

Intrauterine growth restriction (IUGR) has a variety of causes and this article will focus on those which may be related to pathology of the trophoblast – so-called placental insufficiency. The main message we wish to convey is that the aetiology of these cases of IUGR is not solely related to abnormalities of uterine or umbilical bloodflow but is also likely to involve specific placental transport mechanisms. Amino acid transporters, in particular, are implicated.

Chronic fetal growth restriction is associated with both increased perinatal mortality and impaired neurodevelopment. Although it is a much more important cause of fetal neurological damage than intrapartum birth asphyxia, it is more difficult to treat, since the main intervention, timed delivery, carries its own risks. Since it is associated with a range of circulatory changes, which may also cause fetal damage, understanding these may improve management. In this article we review these fetal circulatory changes and assess their significance for predicting perinatal and long term neurodevelopmental outcome. We describe the Doppler assessment techniques, their clinical role in prediction of adverse outcome and the pathogenesis of brain injury in the preterm growth restricted fetus.

Intrauterine growth restriction (IUGR) remains a major cause of perinatal morbidity and mortality and, as yet, there is no effective treatment. Most fetuses with ultrasound evidence of moderate to severe IUGR do not grow better out of the womb than in, despite early enteral feeds and subsequent calorie supplementation. Research into possible therapies for growth restricted babies has thus also been directed towards the fetus. Major advances have been made in recent years in the understanding of the physiology of fetal growth, and it has become clear that fetal nutrition is the determining factor.

The intrapartum management of the twin pregnancy has remained a controversial and challenging issue in obstetrics. Development of a management plan for delivery of a twin gestation necessitates consideration of multiple factors including fetal presentations, gestational age, estimated fetal weights, the presence of maternal or fetal complications, and the experience of the attending obstetrician, anaesthetic staff and neonatologists. In twin gestations in which a trial of labour is possible, the major factor determining the intrapartum course is the relative presentations of twin A and twin B on admission to the delivery suite.

Pharmacological analgesia given to a mother during labour may affect the fetus and newborn in a number of ways. Firstly a drug may cross the placenta and exert a direct effect on the baby. Secondly a method of analgesia may alter maternal physiology or biochemistry and in so doing it may have an indirect effect on the baby. Thirdly it may affect the interaction between mother and baby after delivery. This latter aspect is rather the province of the psychologists. The effects on the baby of different methods of anaesthesia for operative delivery are well researched but are more exclusively the responsibility of anaesthetists and therefore of less import to obstetricians than is analgesia. These will be discussed only insofar as research findings may also be applicable to analgesic methods.

Fetal renal pelvic dilatation (pyelectasis) is readily identified at the routine second trimester anomaly scan. It is now well recognised that mild pyelectasis is associated with fetal chromosomal abnormalities and may predict neonatal renal anomalies. The reported prevalence of pyelectasis and the strength of the association with both aneuploidy and paediatric outcome varies considerably in the literature, making accurate prenatal counselling very difficult.

Most transmission of hepatitis B virus (HBV) infection occurs around the time of delivery through contact with contaminated vaginal secretions or blood. Hence, interventions to reduce vertical transmission of HBV depend on identification of the infected woman during pregnancy so that the newborn infant exposed to infection can be given immunoglobulin immediately after birth, and a course of immunization can be started.

Sonography during the first trimester of pregnancy is essential in twin pregnancies. This is due to the fact that a short two minute scan can reliably determine chorionicity and amnionicity. However, if the scan is not performed until the second or third trimester, the determination of chorionicity and amnionicity may be tedious and time consuming at the end of which many competent sonographers will frequently mis-assign chorionicity and amnionicity. A first trimester scan can therefore determine the appropriate management of the patient for the entire duration of the pregnancy.

Hydrocephalus is a pathological increase in intracranial cerebrospinal fluid, usually within the lateral ventricles and often, although not always, associated with an increase in intracranial pressure and an abnormally large biparietal diameter. Ventriculomegaly simply means enlargement of the lateral cerebral ventricles. The reported incidence of hydrocephalus at birth is 0.5–3 per 1000. The incidence of ventriculomegaly diagnosed antenatally by ultrasound (atrium 10–15mm), varies from 1.48 per 1000 (8/5400) to 22 per 1000 (11/500), the latter study being in a low risk population.

Approximately 1 in 4 of all babies are born with cord round the neck. Being such a common obstetric condition, there is a view that nuchal cord ordinarily does no harm. A number of studies have recognised cord round the fetal neck as a significant cause of fetal death in utero and perinatal morbidity. However, many obstetricians have different views about the significance of nuchal cord as a cause of perinatal morbidity and mortality.