In this article we present a novel model for how the human placenta might get infected via the hematogenous route. We present a list of diverse placental pathogens, like Listeria monocytogenes or Cytomegalovirus, which are familiar to most obstetricians, but others, like Salmonella typhi, have only been reported in case studies or small case series. Remarkably, all of these organisms on this list are either obligate or facultative intracellular organisms. These pathogens are able to enter and survive inside host immune cells for at least a portion of their life cycle. We suggest that many blood-borne pathogens might arrive at the placenta via transportation inside of maternal leukocytes that enter the decidua in early pregnancy. We discuss mechanisms by which extravillous trophoblasts could get infected in the decidua and spread infection to other layers in the placenta. We hope to raise awareness among OB/GYN clinicians that organisms not typically associated with the TORCH list might cause placental infections and pregnancy complications.
In a non-obstetric population, the optimization of cardiac output (CO) had been shown to improve survival and to reduce postoperative complications, organ failure and the length of stay1. CO monitoring might be very useful in the obstetric population as well, as physiologic changes of CO during pregnancy are mandatory for a normal outcome. An uncomplicated pregnancy is associated with a 50% increase in maternal CO, which is mediated by plasma volume expansion and a decrease in peripheral resistance2. An aberrant change of this maternal CO might influence pregnancy outcome: pregnancies complicated with foetal growth restriction and/or preeclampsia are characterized by increased total vascular resistance and reduced systolic function (i.e. lower CO and stroke volume (SV))3–5.
The possibility of prenatal screening for genetic disorders was raised as early as the mid-1950s, and with the introduction in 1966 of amniocentesis for sampling fetal material, it became possible to identify pregnancies with trisomy 21 (Down syndrome), the most common prenatal genetic abnormality. The fetal cells in the amniotic fluid could be cultured, then harvested, followed by chromosome spreading on microscope slides. These chromosome spreads, each representing the chromosomes from a single cell nucleus, could be stained, visualised by light microscopy and counted to establish the chromosome number. However, diagnosis of Down syndrome was expensive, and in the early days of amniocentesis, there was an associated risk of miscarriage; most countries therefore recommended this procedure only for women who were identified as having a raised risk of chromosome abnormality. As it is well established that raised maternal age increases the risk of Down syndrome, amniocentesis was first offered only to women above an age cut-off (usually 35). However, although the risk to an individual woman of having a Down syndrome pregnancy is greater in this age group, the majority of Down syndrome babies are born to younger women, due to the preponderance of pregnancies in the younger group.
The ability to obtain fetal material that could be used for prenatal genetic diagnosis without requirement for an invasive test was a watershed moment in antenatal care. Cell-free fetal DNA (cffDNA) was identified in the maternal plasma by Lo and colleagues in 19971and despite being technically challenging, non-invasive tests for fetal sex determination, fetal rhesus D (RHD) genotyping, some single gene disorders and the major aneuploidies are now being offered in clinical practice throughout the world2. Progress continues at pace and recent developments in next generation sequencing (NGS) are driving significant advances in research and in the clinical application of non-invasive prenatal testing (NIPT) and diagnosis (NIPD) (Table 1).
Spatio-temporal image correlation (STIC) is a feature of four-dimensional ultrasonography (4D US) that allows the acquisition of volume datasets akin to blocks of pathological specimens, where all the anatomical information is contained in the block and the information displayed depends on the level at which the block is cut. STIC has the additional advantages that these planes can be assessed in a virtual beating heart, and that rendering techniques can be used to gain additional insight into the structure and function of the fetal heart.
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The first clinical trials of gene therapy in the 1990s offered the promise of a new paradigm for the treatment of genetic diseases. Over the decades that followed the challenges and setbacks which gene therapy faced often overshadowed any successes. Despite this, recent years have seen cause for renewed optimism. In 2012 Glybera™, an adeno-associated viral vector expressing lipoprotein lipase, became the first gene therapy product to receive marketing authorisation in Europe, with a licence to treat familial lipoprotein lipase deficiency. This followed the earlier licensing in China of two gene therapies: Gendicine™ for head and neck squamous cell carcinoma and Oncorine™ for late-stage nasopharyngeal cancer. By this stage over 1800 clinical trials had been, or were being, conducted worldwide, and the therapeutic targets had expanded far beyond purely genetic disorders. So far no trials of gene therapy have been carried out in pregnancy, but an increasing understanding of the molecular mechanisms underlying obstetric diseases means that it is likely to have a role to play in the future. This review will discuss how gene therapy works, its potential application in obstetric conditions and the risks and limitations associated with its use in this setting. It will also address the ethical and regulatory issues that will be faced by any potential clinical trial of gene therapy during pregnancy.
Calcium is an important element of body composition 1,2 as well as normal physiological functions 3 . A neonate's body has around 20–30 g calcium present at birth 2,4–6 and this amount has to be supplied by the mother since human body cannot synthesise calcium 2 . Therefore, if the mother has a shortage of calcium, the foetus might be affected.
Physiological changes associated with pregnancy are well documented, the liver is no exception. Changes to maternal physiology during pregnancy can give rise to a change in liver function tests.
Artificial reproductive technology (ART) was first introduced to clinical practice in the late 1970s1 and has subsequently resulted in approximately 5 million births worldwide2. Globally, the rates of assisted conceptions continue to rise3. In 2011, approximately 1.5% of all pregnancies in the US were conceived using ART4. Since its introduction, much interest has been generated regarding the effects of ART on the developing fetus and potential adverse impacts on the health of the mother. In particular, early studies suggested an increase in fetal genetic and structural anomalies, and a high risk of perinatal complications. As experience with pregnancies conceived using ART has increased worldwide and more data regarding the outcomes of ART-conceived pregnancies have been reported, many of the initial worries have been shown to be unfounded. However, concern still exists regarding whether any adverse fetal and maternal outcomes result from the use of this technology. Many studies have reported higher risks of fetal complications following the use of ART including an increase in perinatal mortality, even in singleton pregnancies5,6. However, interpretation of these data are far from simple and it is important to consider that observations of higher rates of complications do not equate to a causal relationship between adverse pregnancy outcomes and the use of ART7. There are multiple confounding factors that may account for these associations, many of which are difficult to control for in large-scale studies.
Management of the antenatal compromised airway is a situation that can at best be controlled and managed in a way that is safe for both mother and baby. As the 16th century author, Miguel de Cervantes wrote“Forewarned, forearmed; to be prepared is half the victory”, in a similar fashion we, as clinicians involved in the management of neonatal airways must recognise and prepare for all eventualities in order to produce the best outcomes for our patients. In this review, we discuss strategies in managing the compromised neonatal airway along with specific pathologies that may cause post-natal airway compromise. With each sub-group of pathologies, we suggest potential strategies that can be considered in their management.
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Preterm birth may be spontaneous or medically indicated for maternal or fetal reasons. Around 20–25% of preterm births (PTB) follow preterm premature rupture of the membranes (PPROM), however the cause of preterm labour is often unknown. It may represent early maturation and activation of the normal labour process or it may be precipitated by pathological causes. The normal process of labour has a diurnal variation with more deliveries occurring at night. Evidence demonstrating that the diurnal variation persists in preterm deliveries suggest that at least a proportion are due to early maturation of the normal process and the logical assumption is that these may be amenable to prevention or effective treatment. Whatever the cause of preterm delivery, there appears to be a common pathway resulting in activation of inflammatory processes. It is important to distinguish the physiological and pathological causes of preterm labour and not to assume that all inflammation is pathological. The distinction is clinically important since pathological causes may be associated with an adverse intrauterine environment, which would be a contraindication to delaying delivery.
The incidence of twin pregnancy has risen substantially over the past decade, likely largely as a consequence of artificial reproductive technologies. The perennial dilemmas that apply to any singleton delivery, such as intrapartum monitoring and operative interventions are compounded by the presence of the second fetus. There is no doubt that the conduct of a twin delivery remains one of the most challenging events in the daily practice of obstetrics.
Fetal growth restriction (FGR) is defined as the failure of a fetus to attain its full genetic growth potential. It is a leading cause of stillbirth, prematurity, cerebral palsy and perinatal mortality. Small size at birth increases surviving infants’ lifelong risk of adverse health outcomes associated with the metabolic syndrome. The pathophysiology of abnormal fetal growth is extremely complex and incompletely understood, with a plethora of genetic, signalling and metabolic candidates under investigation, many of which may result in abnormal structure and function of the placenta. In contrast to, or maybe because of, the underlying complexities of FGR, the strategies clinicians have for identifying and managing this outcome are conspicuously limited. Current clinical practice is restricted to identifying pregnancies at risk of FGR, and when FGR is detected, using intensive monitoring to guide the timing of delivery to optimise fetal outcomes. Abnormal Doppler indices in the umbilical artery are strongly associated with poor perinatal outcomes and are currently the “gold standard” for clinical surveillance of the growth-restricted fetus.
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Preterm birth (PTB) has a global prevalence of 11.1% accounting for almost 15 million babies born each year before 37 weeks of gestation. It is a risk factor in over 50% of all neonatal deaths, which amounts to 1.1 million deaths annually. Preterm birth, especially at early gestational ages is associated with a high risk of long-term morbidity in survivors. Despite much research effort, PTB rates continue to rise, placing immense financial and emotional burden on society. In the US, the annual societal economic cost associated with PTB is $26.2 billion with an average of $51,600 being spent per infant born preterm. Preterm labour (PTL) accounts for 70% of these births, of which 25% are preceded by preterm pre-labour rupture of membranes (PPROM).
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Congenital cytomegalovirus (CMV) infection is now the commonest infective cause of neurological handicap. Arguably, there is no other single contributor to developmental disability where a greater opportunity, and imperative, exists to improve outcomes than CMV. CMV is the most common intrauterine infection and congenital CMV is the leading non-inherited cause of sensorineural deafness. The public health impact of CMV is significant: the overall birth prevalence of congenital CMV is estimated at 0.64%, with 11% of live born infants displaying symptoms.
Endothelial cell proliferation and survival require continuous low levels of vascular endothelial growth factor (VEGF). The bioavailability of this angiogenic factor appears to be regulated by anti-angiogenic factors, including the soluble form of VEGF receptor 1 (sFlt-1) in the non-pregnant and pregnant states. During pregnancy a VEGF antagonist (sFlt-1) and other anti-angiogenic factors, including soluble endoglin (s-Eng), are produced by the human placenta and released into the maternal circulation; an excess of these anti-angiogenic factors can lead into angiogenic imbalances and pregnancy complications. This is important because regulation of VEGF action on angiogenic balances appears to be essential for a successful pregnancy.
