Flow is defined as the amount of fluid, ordinarily blood, passing per unit time (usually per minute). Perfusion is defined as the volume of blood flowing through a mass of tissue per unit time. The standard measure of perfusion is millilitres of fluid per second per 100 g of tissue (or 100 ml in volume) i.e. the fractional blood volume in an area divided by the mean transit time through the area, where the area is scaled to a 100 ml of tissue. The fractional vascular volume is an index of the physiological vascularity of a region and represents the proportion of tissue occupied by blood. Several ultrasound based techniques have been used in an attempt to quantify perfusion. Vessel dimensions of capillaries and arterioles are below the spatial resolution of even the latest ultrasound machines, and capillary flow is slower than that required to generate a Doppler signal which leads to underestimation of true perfusion. For all ultrasound-based techniques movement artefacts are probably the greatest obstacle to obtain quantitative information on perfusion. This review will discuss the technology and use of the ultrasound mode of three dimensional power Doppler, its benefits and limitations in estimating vascularity focusing on the field of obstetrics.

Interest in the clinical associations between maternal intrapartum fever and adverse neonatal outcome has been longstanding, with publications of a relationship between maternal fever and cerebral palsy dating from the 1950s. Further recognition of the associations between either clinically or histologically characterised chorioamnionitis, ascending infection and neonatal wellbeing followed, with numerous reports in the 1960s and 70s, particularly as the neonatal significance of group B streptococcal infections became apparent. Similarly, with the systematic introduction of diagnostic light microscopy into clinical medicine, chorioamnionitis (inflammation of the placental membranes) and funisitis (inflammation of the umbilical cord) were recognised as distinct histological entities, with increasing recognition that the aetiology was likely to be infective. There are numerous texts discussing in detail the pathogenesis and histological features of chorioamnionitis and funisitis. The aim of this review is to provide an overview of the salient associated issues for clinical practitioners and to highlight areas of ongoing uncertainty and recent developments in understanding.

Screening for Down syndrome is an important part of routine antenatal care and should be made available, if requested, after appropriate counselling including risks and benefits, to all pregnant women, regardless of maternal age. Prenatal screening for fetal Down syndrome and other aneuploidies has advanced significantly since its advent in the 1980s. Historically, women 35 years or older were offered prenatal genetic counselling and the option of a diagnostic test such as chorionic villus sampling or amniocentesis. With this screening approach only 20% to 30% of the fetal Down syndrome population are detected antenatally. Sonographic and maternal biochemical markers are now used in combination to screen for aneuploidies in the first and second trimesters. The most common screening method in the first trimester combines the maternal serum markers HCG and PAPP-A with the sonographic evaluation of fetal nuchal translucency thickness. Newer markers have been proposed to further refine the risk assessment for Down syndrome to maximise detection rates and minimise false positive rates. These newer first trimester markers include sonographic assessment of the fetal nasal bone (NB), the frontomaxillary facial (FMF) angle, ductus venosus (DV) Doppler and tricuspid valve regurgitation (TR).

At the end of 2007, Time magazine listed the “benefits of vitamin D” as one of its top 10 medical breakthroughs for that year. Since then there has been a remarkable upsurge of interest in vitamin D, with new research advances seemingly published on a weekly basis. In particular, there has been increasing awareness of the variability of vitamin D status in populations across the globe and, significantly, a growing debate about the need for revised parameters for vitamin D supplementation. Although sub-optimal vitamin D is likely to be a widespread problem for 21st century societies, it is also clear that some groups are at much greater risk of low vitamin D status. Prominent amongst these are pregnant women and the aim of the following review article will be to discuss this problem in further detail with specific emphasis on its potential physiological and clinical impact.