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The hypothesis of this work is that through establishing the background variation of ultrasonographic fetal biometry measurements and elucidating the parameters that influence these measurements, a new Fetal Ultrasound Biometry Quality (FUB-Q) image-scoring tool can be created which will be reproducible and able to quantify the accuracy of fetal measurements. Six studies are included, each answering a specific research question. The aim of the first study was to ascertain whether pre-existing image quality scoring methods reflect measurement accuracy and reproducibility. It demonstrated that during the course of an exercise where there was demonstrable improvement in the consistency of measurements performed - by a group of sonographers, this was not mirrored by the pre-existing image scoring system. The aim of the second study was to establish the intra- and inter- observer variability of fetal biometry measurements throughout pregnancy by expert sonographers. This study demonstrated that ultrasound variability of fetal biometry increases with advancing gestation when expressed in measurement values, but is constant as a percentage of the fetal dimensions or when reported as a z score. Calliper placement was the major component of the overall variability. The values from this study served as the background variability, "reference standard", for the FUB-Q tool. The third study had two aims. The first was to establish how 3D scanning performs compared to conventional, real-time, 20. The second aim was to assess whether off-line 3D volume manipulation can be used as a tool to substitute real-time 20 ultrasound for the subsequent studies. It demonstrated that measurements using 3D volume acquisitions exhibit good agreement with real-time 20 scanning, with no systematic error but with a higher random error. However, it also demonstrated that 3D scanning is slower to perform and, similar to real-time 2D, it is not always possible to acquire a 3D volume from a desired orientation. Furthermore, not all 3D volume acquisitions were amenable to reconstruction. However, this study showed that saved 3D volumes can be used as a mean to store large volumes of data for later detailed analysis. The aim of the fourth study was to create the FUB-Q scoring tool. This was done by establishing the difference in measurement resulting from optimal and different forms of suboptimal images in a systematic fashion. For any . t " given image, and its derived measurement, the observer inserts in the model the various image scoring point parameters. The model then gives a prediction about the confidence interval within which the optimal, "gold standard", measurement should be. The aim of the fifth study was to validate on an independent test set the predictive ability of the newly developed FUB-Q scoring tool. It demonstrated that the FUB-Q tool can correctly predict the confidence interval within which measurements recorded from correctly acquired images should be in relation to measurements acquired from incorrectly acquired ones. The aim of the sixth, and final , study was to evaluate the reproducibility of obtaining the relevant scores for the FUB-Q tool. It demonstrated that the FUB-Q tool has good intra- and inter- observer reproducibility and is a reliable system for assessing the quality of fetal biometry based on ultrasound images. In conclusion, the FUB-Q tool could be a useful system used for audit of clinical practice and quality control as well as for training purposes .

The local actions of glucocorticoids are modulated by 11βhydroxysteroid dehydrogenase (ll~HSD) enzymes which catalyse interconversion of cortisol with its inert metabolite, cortisone. Expression and activity of 11βHSD enzymes has not been well characterised in the first trimester placenta. The aims of this study were to determine the effects of glucocorticoids on trophoblast, and to establish whether glucocorticoid metabolism differs in first trimester placentae from pregnancies at a higher risk of developing pre-eclampsia compared to low risk pregnancies (as determined by uterine artery Doppler ultrasound scanning). Cortisol treatment led to a small increase in extravillous trophoblast (EVT: SGHPL-4 cell line) motility as determined by time-lapse microscopy. Neither cortisol nor cortisone altered trophoblast invasion. ) 11βHSD2 expression was detected in first trimester placental tissue, and was localised to syncytiotrophoblast. Immunocytochemistry confirmed 11βHSD2 expression in EVT explant outgrowths and SGHPL-4 cells. No 11βHSD1 expression was detected. Glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) expression were both detected in EVT. MR was detected in placental tissue by western blot analysis, but not immunohistochemistry. Enzyme assays confirmed that the 11βHSD2 enzyme inactivates cortisol in first trimester placental tissue. Net cortisol oxidation was significantly greater in placental tissue from pregnancies at higher risk of pre-eclampsia than in lower risk pregnancies; however there was no difference In 11βHSD2 expression. The 11βHSD2 enzyme is thought to protect the fetus from exposure to maternal cortisol. While other studies have suggested that 11βHSD2 is decreased in term pre- eclamptic placentae (relative to normotensive pregnancies), this study suggests that there is increased 11βHSD2 activity in first trimester placentae from pregnancies at higher risk of developing pre-eclampsia. This increase in enzyme activity is not accompanied by an increase in expression of 11βHSD2 consistent with post- translational regulation of enzyme activity. It remains to be determined if this difference is related to the pathophysiology of pre-eclampsia or is a compensatory response to poor trophoblast development.

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L’environnement (E) du grand prématuré (GP) diffère de l’E. utérin et contribue aux séquelles neurosensorielles qui le menace. Les stimuli auditifs y sont prédominants et atypiques. Peu de choses sont connues sur la sensibilité auditive du GP à ces stimuli. Elle est évaluée ici par l’analyse de sa réactivité physiologique, comportementale, et cérébrale (NIRS) aux variations de cet E. Une étude observationnelle montre que i) le GP réagit à des stimuli auditifs dès un seuil de 5-10 dBA de ratio signal-bruit ambiant ; ii) certaines stimulations altèrent son bien-être (désaturations, rupture du sommeil) ; iii) ses réponses autonomiques sont les plus sensibles. Sa réactivité varie selon la source sonore, suggérant une discrimination du caractère vocal ou non des stimuli. Une étude expérimentale évalue d’autres aspects de ses performances auditives (impact de la fréquence sonore, de la valence émotionnelle des voix) et leur maturation de 30-32 à 34-36 sem. d’âge post-menstruel. Son champ de perception fréquentiel de sons purs s’élargit des moyennes (500-2500 Hz) aux basses et hautes fréquences (100 et 4500 Hz). Après 34 sem., il discrimine la voix maternelle de celle d’une autre mère et d’une autre femme (émotionnellement neutre). Cette réactivité préférentielle se traduit par un « réflexe cardiaque d’orientation » et témoigne qu’un GP soustrait précocement à la voix de sa mère développe des capacités perceptives similaires à celles du fœtus exposé en continue à la prosodie de la voix maternelle. Ces résultats ouvrent un champ de recherche complémentaire sur les conséquences à long terme de son expérience auditive précoce (attachement, développement du langage et des émotions). / The environment (E) of very preterm infant (VPI) greatly differs from the uterine E and contributes to his risk of altered neurodevelopment. Although auditory stimuli are prominent and atypical in the NICU, little is known about the auditory sensitivity of VPI to his acoustic E. It is evaluated through their physiological, behavioral, and brain (NIRS) responsiveness to auditory environmental changes. An observational study shows that i) VPIs respond to “naturalistic” auditory stimuli from a minimum signal-to-noise ratio threshold of 5-10 dBA, ii) some stimuli can affect their well-being (desaturation, sleep disruption), iii) their autonomic reactivity is the most sensitive. Their reactivity varies depending on the sound sources, suggesting an ability to discriminate vocal from non vocal sounds. An experimental approach assess other aspects of their auditory performance (impact of sound frequency, emotional valence of voices) and their maturation from 30-32 to 34-36 wks post-menstrual age. Their perceptual field of sound frequencies expands for pure tones from the middle frequencies (500-2500 Hz) to low and high frequencies (100 and 4500 Hz). After 34 wks, VPIs discriminate their mother's voice from that of another mother and of another woman (emotionally neutral). This preferential reactivity relies on a "cardiac orienting reflex" suggesting that VPI not exposed for weeks to their mother’s voice in utero, can develop perceptual abilities similar to those of the fetuses continuously exposed to the prosody of their mother’s voice. They open ways for further research on the long-term consequences of early auditory experience (attachment, language and emotions development).

Preimplantation genetic diagnosis (PGD) refers to the testing of embryos produced through in vitro fertilization (IVF) in order to identify those unaffected by a specific genetic disorder or chromosomal abnormality. In this study, different methodologies were examined and developed for performance of PGD. Investigation of various whole genome amplification (WGA) methods identified multiple displacement amplification as a reliable method for genotyping single cells. Furthermore, this technology was shown to be compatible with subsequent analysis using single nucleotide polymorphism (SNP) microarrays. Compared to conventional methods used in this study to perform single cell diagnosis (e.g. multiplex PCR), WGA techniques were found to be advantageous since they streamline the development of PGD protocols for couples at high risk of transmitting an inherited disorder and simultaneously offer the possibility of comprehensive chromosome screening (CCS). This study also aimed to develop a widely applicable protocol for accurate typing of the human leukocyte antigen (HLA) region with the purpose of identifying embryos that will be HLA-identical to an existing sibling affected by a disorder that requires haematopoietic stem cell transplantation. Additionally, a novel microarray platform was developed that, apart from accurate CCS, was capable of reliably determining the relative quantity of mitochondrial DNA in polar bodies removed from oocytes and single cells biopsied from embryos. Mitochondria are known to play an important role in oogenesis and preimplantation embryogenesis and their measurement may therefore be of clinical relevance. Moreover, real-time PCR was used for development of protocols for CCS, DNA fingerprinting of sperm samples and embryos and the relative quantitation of telomere length in embryos (since shortened telomeres might be associated with reduced viability). As well as considering the role of genetics in terms of oocyte and embryo viability assessment and the diagnosis of inherited genetic disorders, attention was given to a specific gene (Phospholipase C zeta) of relevance to male infertility. A novel mutation affecting the function of the resulting protein was discovered highlighting the growing importance of DNA sequence variants in the diagnosis and treatment of infertility.