Currently, the gold standard for prenatal detection of chromosomal abnormalities relies on traditional cytogenetic analysis of banded meta-phase chromosome spreads of cultured cells obtained by amniocentesis, chorionic villous sampling, or fetal blood sampling. Using this technique, a wide range of chromosomal aneu-ploidies and structural aberrations such as translocations, inversions and deletions may be diagnosed with a high degree of accuracy. Unfortunately, this technique has several disadvantages: it is labour intensive, requiring highly trained analysts, and most importantly, it can only be applied to cells undergoing mitosis. Hence the.need for cell culture which may require several days, such that the complete analysis is usually obtained after 7 to 14 days. Thus, there is a need to develop faster methods for prenatal chromosomal analysis.

In 1971 Shettles postulated that, during pregnancy, chorionic cellular elements from degenerating villi were shed into the endocervical canal and could be analysed to assess fetal sex. Accordingly, he retrieved transcervical cells (TCC's) with cotton swabs and tested them for the presence of the Y chromosome using a fluorescent dye (quinacrine mustard). At the time of publishing his note, he had correctly diagnosed the sex of 10 fetuses in 18 pregnancies investigated.

Despite the fact that most perinatal and maternal complications are on the decline in diabetic pregnancies, the rate of congenital malformations has not changed over the past twenty years.1 In fact, congenital malformations have replaced asphyxia and respiratory distress syndrome as the leading cause of mortality in offspring born to mothers with insulin-dependent diabetes mellitus.2 The frequency of major congenital malformations has been estimated at 6 to 10% representing a three to five fold increase over the rate in the general population.3,4 Congenital malformations in the offspring of women with diabetes represent a significant social and financial burden to society.

Preeclampsia (PE) is a common disease of pregnancy that affects women particularly in their first pregnancies. Current estimates suggest that between 7 and 10% of pregnancies may be complicated by PE. Despite considerable research and medical efforts, the incidence of the disease has not changed substantially in the last century. In severe cases the disease may be life-threatening and is associated with high neonatal mortality and morbidity. Furthermore, therapy is often ineffective and at best treats the disease symptoms rather than the aetiology. One reason for the lack of progress may be that while the disease is generally agreed by most to be due to abnormal implantation and development of the placenta (events which happen in the first trimester) most research efforts have focused on managing and understanding the maternal disease. Since the disease typically appears in the last trimester, many weeks after the likely start of the pathology, it has been difficult to understand the progression of events. However, this picture has improved recently. The purpose here is to review how placental development is affected in PE and describe new insights into the causes. It is hoped that an understanding of the pathogenesis of the placental defects in PE will lead to new efforts towards early diagnosis, before the onset of clinical symptoms, as well as new treatments for these lesions.

Toxoplasmosis is one of the commonest protozoal infections in man. The causative organism, Toxoplasma gondi has been estimated to have infected in the region of 25–50% of the world's population with evidence of serological infection ranging from 2 to 90% depending on the geographical area. The infection is usually harmless and subclinical, the primary infection being rarely diagnosed. However, it can lead to life threatening disease in the immunocompromised patient and a primary infection in pregnancy can have severe sequelae in the fetus.

In monozygotic twin pregnancies embryonic splitting within three days of fertilisation, which occurs in approximately one-third of cases, results in two separate fetuses with independent placental circulations. Splitting after the third day of fertilisation is associated with vascular communications between the placentae; when cleavage is delayed beyond day 12 the fetuses are conjoint. In some monochorionic twin pregnancies imbalance in the net flow of blood across the placental vascular communications from one fetus (the donor) to the other (the recipient) results in twin to twin transfusion syndrome (TTS).

The incidence of pregnancies with three or more fetuses has markedly increased over the past two decades. The change has been attributed to the introduction and widespread use of new techniques for ovulation induction and placement of multiple embryos during in vitro fertilization (IVF). These techniques have been a matter of concern, since triplet and higher multiple pregnancies have long been associated with an increased risk of maternal complications, and a high prevalence of perinatal and neonatal morbidity and mortality. Furthermore, the developing experience with multifetal pregnancy reduction offers a new option for the management of these pregnancies. There is therefore a need to evaluate the management and outcome of high-order multiple pregnancies.

Cerebral palsy has been defined as a group of non-progressive disorders of movement or posture due to a defect or lesion of the immature brain.1 Cerebral palsy is defined by clinical description only; there is no definitive test. It is not informative about aetiolgy, pathology or prognosis. The definition of cerebral palsy also lacks precision in that neither the age at which the brain is mature nor the severity of the disorder required are specified. Brain development is most rapid in utero and early childhood but continues at a diminished rate throughout life. There is therefore no biological rationale for choosing any particular age to define brain maturity. The defining age below whcih cerebral palsy may be recognised therefore varies between centres for pragmatic reasons usually associated with assertainment. For example, in Western Australia the criterion is set at 5 years,2 since by this age any central motor impairments of congenital or neonatal origin will be apparent and can usually be differentiated from progressive disorders or isolated motor delay. Thus the definition includes a group of children with post-neonatally acquired brain damage resulting in movement disorder. Post-neonatally acquired cerebral palsy differs from presumed congenital or perinatal cerebral palsy in that there is usually no doubt that it was caused by a specific post-neonatal event such as meningitis or head trauma. Although there is an excess of perinatal morbidity amoung children acquiring cerebral palsy post-neonatally,3 suggesting a prior vulnerability in some cases, post neonatally acquired cerebral palsy will not be considred further in this review.

Meconium ileus (MI) is one of the most common causes of intestinal obstruction in the newborn accounting for 9–33% of neonatal intestinal obstructions. It is the earliest clinical manifestation of cystic fibrosis (CF), occurring in approximately 16% of patients with CF. However, MI has been reported in the absence of CF.

Preeclampsia was originally known as a process whereby an unknown “toxin” was responsible for a variety of responses. While this toxin has yet to be determined, many theories have prevailed as to the appropriate therapy for this condition.

Recently, antihypertensive therapy has become increasingly regarded as an important component of the medical management of women with preeclampsia. Initially, the ideal therapy for peripartum acute hypertensive emergencies was felt to be a smooth muscle relaxant and the most commonly prescribed agent was hydralazine. This drug was felt to be beneficial because of its action on vascular smooth muscle, decreasing vasospasm. Outside of the United States diazoxide was also used for this purpose, although this drug has been replaced because of the high incidence of fetal distress. Another agent that was frequently used was α-methyldopa which was initially considered to be the treatment of choice in the treatment of patieats with moderate and severe preeclampsia. Recently, α-methyldopa has been reserved for the outpatient management of gestational hypertension, especially in women with mild preeclampsia or chronic hypertension.

In most pregnancies labour begins at term in the presence of intact fetal membranes. Without intervention the membranes usually spontaneously rupture near the end of the first stage of labour. In 10% of pregnancies that deliver at term the fetal membranes fail to maintain their structural integrity and this results in their “prelabour rupture”, defined as spontaneous rupture of membranes at least one hour before the onset of labour. In 95–98% of these cases at term, labour is precipitated within 48 hours. Although preterm birth, defined as birth prior to 37 completed weeks of pregnancy, occurs in only 7–8% of all pregnancies, 40–60% of these deliveries are preceded by prelabour rupture of the fetal membranes.

The use and method of intrapartum obstetric analgesia has remained controversial since the late 16th Century. In 1591, during the reign of James, VI, Eufame MacCalzean (a Scottish midwife) was the first to attempt pain relief during labour and childbirth. At that time, the provision of pain relief during labour was an unacceptable medical practice due mainly to religious and social objections. Because of these objections, and historical accounts that claimed the midwife had consulted with a witch during the delivery, both MacCalzean and the midwife were found guilty of witchcraft and subsequently executed.

Pregnant women have traditionally been discouraged from participating in physically demanding sports because they have been considered to be in poor condition and it was thought that strenuous exercise could harm the mother and the fetus. More recently, however, many physically active women have wished to continue sport in pregnancy and research over the past 20 years has shown that in general it is safe to do so.

Despite advances in obstetric and neonatal care, hypoxia-ischaemia remains as probably the commonest cause of severe disabling brain injury which occurs in the perinatal period. Although for the population as a whole, congenital brain abnormality and early fetal events are the most frequent antecedent of permanent neurodevelopmental disability, perinatal brain injury is an important and potentially preventable cause of severe and permanent handicap in both developed and developing countries.

Preterm delivery occurs in less than 10% of pregnancies but accounts for more than 60% of all neonatal deaths. Approximately one third of preterm deliveries are associated with preterm prelabour amniorrhexis and in a high proportion of such cases the underlying cause may be ascending infection from the lower genital tract. The causes of neonatal death in pregnancies with amniorrhexis are prematurity, pulmonary hypoplasia and sepsis. In the management of pregnancies with preterm prelabour amniorrhexis it is essential to distinguish between those with and without intrauterine infection. If there is no infection at presentation it is unlikely that this will develop and in such cases there is no benefit from hospitalisation, bed rest, prophylactic tocolytics or antibiotics. The group with evidence of intrauterine infection go into spontaneous labour within a few days of amniorrhexis; in this group the main determinant for the appropriate management is the gestation at amniorrhexis.

One aim of obstetric practice is to ensure the wellbeing of the fetus. This is by no means an easy task and recent years have seen the development of a variety of tests, with varying degrees of success, to evaluate fetal health.

Fetal wellbeing may be assessed at a variety of levels: genetic/cellular, physical/structural or functional. Ideally the evaluation of fetal health should provide information about the functional outcome of any particular condition, especially the performance of the central nervous system. Current tests may not do this. Thus, whilst tests of the fetal chromosomal or genetic constitution may determine the presence of particular genetic/chromosomal conditions, they may not predict functional outcome especially the functioning of the cerebral cortices, the ultimate arbiter of excellence in man. For example, Down's syndrome may be accurately diagnosed by analysis of fetal cells to detect the presence of Trisomy 21 but this in itself provides little information on the subsequent functional performance of the individual. The development of tests of fetal heart function such as antenatal cardiotocography have provided a means of assessing cardiac function and, to a certain extent, the functioning of parts of the autonomic nervous system. However such tests can only indirectly assess cortical function.