Causes and Mechanisms of Intrauterine Hypoxia and Its Impact on the Fetal Cardiovascular System: A Review

Until today the role of oxygen in the development of the fetus remains controversially discussed. It is still believed that lack of oxygen in utero might be responsible for some of the known congenital cardiovascular malformations. Over the last two decades detailed research has given us new insights and a better understanding of embryogenesis and fetal growth. But most importantly it has repeatedly demonstrated that oxygen only plays a minor role in the early intrauterine development. After organogenesis has taken place hypoxia becomes more important during the second and third trimester of pregnancy when fetal growth occurs. This review will briefly adress causes and mechanisms leading to intrauterine hypoxia and their impact on the fetal cardiovascular system

Impacted fetal head at caesarean section:a national survey of practice and training

This is a national survey of UK obstetric trainees and consultant labour ward leads designed to investigate the current practice and training for an impacted foetal head (IFH) at Caesarean Section (CS). An anonymous, on-line survey was disseminated to trainees via Postgraduate Schools and RCOG trainee representatives, and to labour ward leads via their national network. Three hundred and forty-five obstetric trainees and consultants responded. The results show that IFH is variably defined and encountered by most UK obstetricians (98% had encountered IFH and 76% had experienced it before full cervical dilatation). There is significant variation in management strategies, although most respondents would use a vaginal push up to assist delivery prior to reverse breech extraction. Responses revealed a paucity of training and lack of confidence in disimpaction techniques: over one in ten respondents had not received any training for IFH and less than half had received instruction in reverse breech extraction.Impact statement What is already known on the subject? IFH is an increasingly recognised, technically challenging complication of intrapartum CS. A recent report suggested that birth injuries associated with IFH are now as common as with shoulder dystocia. However, there is no consensus nor guidelines regarding the best practice for management or training. What do the results of this study add? This study demonstrates that IFH is poorly defined and commonly encountered by UK obstetricians. It highlights that IFH is not restricted to CS at full dilatation and reveals the ubiquity of the vaginal push method in UK practice. We found evidence that UK obstetricians are using techniques which have not been investigated and are not recommended for managing an IFH. Moreover, this survey is an eye-opener as to the paucity of training, highlighting that UK obstetric trainees are not adequately prepared to manage this emergency. What are the implications of these findings for clinical practice and/or further research? There is a pressing need to standardise the definition, guidance and training for IFH at CS. Further research should clarify the appropriate techniques for IFH and establish consensus for the best practice. An evidence-based simulation training package, which allows clinicians to learn and practice recognised disimpaction techniques is urgently required

Intrauterine growth restriction is associated with persistent juxtamedullary expression of renin in the fetal kidney

Intrauterine growth restriction is associated with persistent juxtamedullary expression of renin in the fetal kidney.BackgroundIntrauterine growth restriction (IUGR) has been linked to impaired renal function and hypertension, suggesting that an adverse prenatal environment could alter kidney development and renin production.MethodsImmunohistochemistry and in situ hybridization were employed to localize renin-containing cells (RCCs) in the deep, middle, and superficial zones of autopsy kidney sections, in parallel with histologic maturation, from unexplained stillborn fetuses of normal weight (N = 26) and stillborn fetuses with IUGR (N = 17).ResultsIn the control group, the number of RCC per 100 glomeruli in the deep zone decreased with advancing gestation from 40 at 20weeks gestation to five at term (P < 0.001), whereas the opposite change was found in the superficial zone (increase from 5 per 100 to 55 per 100; P < 0.001). In the IUGR group, the density of RCCs in both the superficial and deep zones was similar to the control group at 20weeks, and no shift in renin gene expression was observed as gestation advanced. Histologic maturation was unaltered.ConclusionsRenin gene expression persists and predominates in the deep renal cortex of the stillborn IUGR fetus, and could contribute to the pathogenesis of neonatal oliguria and/or hypertension during postnatal life

Effects of glycol-split low molecular weight heparin on placental, endothelial, and anti-inflammatory pathways relevant to preeclampsia

The authors thank the donors, the Research Centre for Women’s and Infants’ Health BioBank program, the Lunenfeld-Tanenbaum Research Institute and the MSH/University Health Network Department of Obstetrics & Gynaecology for the human specimens used in this study.Peer reviewedPublisher PD