Chorionic plate (CPA) and stem villous (SVA) arteries located at the fetal and maternal interface of the placenta respond to stimuli including hypoxia and acidic pH which can be the result of an intermittent blood supply. Unlike other vascular tissue the placenta lacks nervous control so any response to such stimuli will be autoregulated by ion channels. Members of the two pore domain potassium channel family (K2P) the Tandem of P domains in a weak inward rectifying (TWIK) related potassium channel (TREK-1) and the TWIK Related acid sensitive K+ channel (TASK-1/3) have been shown to respond to both intracellular and extracellular pH. The hypothesis that there is differential expression and modulation of these candidate ion channels in normal pregnancy was tested. Placentae (N) were collected with written informed consent from healthy patients undergoing elective Caesarean section at term (≥37 weeks). The functional responses of resistance sized arteries (≤500µm) (n) taken from the SVA and the CPA were characterised using wire myography. Vessels were pre-contracted with U46619 and the effect of extracellular pH was studied using 1M lactic acid to produce falls of 0.2 pH units over a range of pH 7.4-6.4. The effects of a variety of ion channel modulators along with tissue oxygenation (20%, 5% and 2% O2) were also investigated on the vascular response of CPA and SVA. Western blot analysis was performed on crude CPA and SVA tissue homogenates with separation by 12% SDS-PAGE to quantify expression of TASK-1/3 and TREK-1. The subcellular localisation of each ion channel was also examined with smooth muscle cells (SMC) cultured from the CPA and SVA by confocal immunofluorescence. CPA and SVA were equally positive for TASK 1/3 (N=31) and TREK 1 (N=40) at the protein level. SMC from CPA and SVA showed expression for TASK 1/3 (N=8) with an increased fluorescence stain around the peri nuclear region. TREK-1 (N=12) expression showed a linear organisation that closely overlapped with α actin IF stain. The acidic pH stimulation triggered a biphasic relaxation that was repeated with each subsequent pH insult. A change from pH 7.4-7.2 produced a 29 ± 3% (n=9) relaxation of CPA which increased to 61 ± 4% at the lowest pH of 6.4 in 20% pO2. Similarly, altering the pH of pre-constricted SVA caused a 21 ± 2% (n=6) fall at pH 7.2 with a maximum relaxation of 69 ± 2% at pH 6.4 (p<0.01). Lowering pO2 from 20% to 5% inhibited the relaxation response seen with CPA (45 ± 3%, n=8) and SVA (34 ± 3%, n=6) at pH 6.4. CPA were also treated with the TREK-1 blocker L-methionine (1mM) which increased the relaxation to 67 ± 7% (n=6 p<0.001) at pH 6.4. Similarly the TASK 1/3 blocker ZnCl2 (1mM) gave a maximum relaxation of 72 ± 5% (n=8 p<0.01) in 20% pO2. The TREK-1 opener riluzole demonstrated a potent relaxation with both CPA (75 ± 5%, n=6) and SVA (78 ± 5%, n=6) in 20% pO2. Our data has shown that tissue oxygenation and extracellular pH within the physiological range has an important role in controlling vasodilatation in the placenta. Protons are readily transported across the cell membrane and can activate a range of targets including the K2P channels. The relaxation by riluzole has not been previously reported and implicates a direct role for TREK-1 in controlling placental vessel function. However, when TREK-1 and TASK-3 channels were blocked, the response by CPA to lower pH was exaggerated, and reflects the complex pharmacology of pH on vascular function. This also suggests that K2P channel activity can be compensated for by other pH sensitive channels and work is currently underway to identify the role of other potential ion channels that may be involved in this pathway.

The ovarian follicle is an individual functional unit that provides the optimal environment for the oocyte within to develop. This thesis outlines the research in the field of ovarian follicular dynamics that has already been established, and further develops these findings to explore in greater detail the relationship between the oocyte and its environment, both in an in vitro and in vivo setting, using a variety of species. The first major research area involved studying the role of oocyte-secreted factors, which was examined using a series of dose response experiments. These were performed using an ovine granulosa cell culture model, and elucidated a possible role for a collaborative action of BMP15 and GDF9 in the promotion of oestradiol synthesis, while inhibiting production of progesterone in this species. This finding was then further investigated using an ovine in vivo immune-neutralisation study, the endocrine and histological results of which confirmed these findings in a proportion of these animals, although this study was limited by the animals appearing to have been in seasonal anoestrus. The second major topic that was investigated was based around the ovarian microenvironment, in terms of angiogenesis and hypoxia. Again, ovine granulosa cell cultures were used, in this instance to examine the effect of hypoxic conditions on steroid hormone production. These experiments indicated that somatic cell steroid hormone production is likely to be compromised by a hypoxic environment, and therefore that the provision of oxygen through a local blood supply may be a vital requirement for these cells. To investigate the relevance of studying ovarian blood supply and physiology in a clinical setting, perfusion studies were carried out based on a series of bovine phantom experiments, which were used to study the effect of varying flow rate on the parameters routinely measured using this technology. The routine clinical ultrasonographic methods of ovarian assessment such as 4D ViewTM, SonoAVCTM and VOCAL were also examined, based on bovine phantom experiments, revealing possible weaknesses in the data provided by ultrasound that are increasingly relied upon in the clinical setting. Finally, a clinical trial was carried out to try and encompass all of the findings of the in vitro and in vivo work, in order to place these theories into context in a human IVF setting. This work was unfortunately limited severely by a lack of patient numbers, but some interesting results were observed with regard to oocyte developmental potential relationships with follicular fluid and somatic cell factors, as well as ultrasound measures of peri-follicular blood supply.

Maternal obesity and diabetes increase the risk of delivering large for gestational age infants (LGA), who have higher risk of long term obesity or metabolic syndrome [1]. As the underpinning mechanisms of how fetal growth is regulated by the placenta remain unclear [2], this thesis has investigated placental responses to high maternal BMI and gestational diabetes. Spanish pregnant women recruited at 20 gestational weeks were classified according to pre-pregnancy BMI as control (BMI<25kg/m2; n=59), overweight (BMI=25-30kg/m2; n=29) or obese (BMI>30kg/m2; n=22), and gestational diabetes status (GDM) classified at 28 weeks. Maternal anthropometry and gestational weight gain (GWG) were measured during pregnancy. Placenta, cord blood, newborn antrophometry and infant weight were sampled or measured. Expression of genes involved in placental energy sensing pathways, folate transporters and DNA methylation was determined using real-time PCR, and placental triglyceride concentrations, lipid peroxidation and genomic DNA methylation patterns measured. Data were analysed according to their parametric distribution by Kruskal-Wallis or 1-way ANOVA. Despite lower GWG, a greater proportion of obese women exceeded recommended weight gain [3], had higher placental weight and increased numbers of LGA infants. Maternal hyperinsulinaemia and hyperglycaemia with obesity were accompanied by unchanged placental IGFR1 and ISR1 expression, similar cord blood glucose and triglyceride concentrations. Placental mTOR was halved with obesity, whilst SIRT1 and UCP2 gene expression were 1.8 and 1.6 fold upregulated respectively with no differences in TBARS concentrations. Hyperleptinaemia in obese women resulted in unchanged placental leptin and leptin receptor expression, but higher cord blood leptin and monocyte concentrations with placental hypermethylation of genes involved in the immune response. Lower folate concentrations in obese mothers led to similar cord blood folate, and decreased placental FRα, but raised DNMT1, mRNA expression. No major differences were observed with GDM, probably due to small sample size. In conclusion, it appears that the placenta can protect the fetus of obese women by increasing antioxidant capacity, compensating for maternal hyperglycaemia and lower folate. However, maternal obesity was associated with enhanced cord blood leptin and monocyte concentrations, increased placental weight and more LGA delivery, leaving infants at ongoing risk of increased adiposity and inflammation. Therefore, current studies are currently exploring these interacting aspects.

Pre-eclampsia is a disorder of unknown aetiology that affects about 5% of Sri Lankan women during their pregnancy. It is most likely a multifactorial disorder that is caused by the interaction of genetic and environmental factors. Recent advances in genetics have resulted in a surge of investigations into genetic factors underlying pre-eclampsia. These studies have been conducted mainly in the white Caucasians in the West and the Japanese in the East. The investigations described in this thesis therefore were undertaken in a genetically distinct South Asian Sinhalese population in Sri Lanka and replicated in a white Caucasian population in Nottingham, UK. Four candidate genes; Epidermal Growth Factor (EGF) and Transforming Growth Factor Alpha (TGFA), which may play a role in placentation; Angiotensinogen (ANG), which is involved in blood pressure regulation; and 5,10-Methylenetetrahydrofolate reductase (MTHFR), which is an enzyme involved in folate metabolism, were examined. These investigations consisted of the following: Recruitment of 80 population volunteers each from the Sinhala, Sri Lankan Tamil and Moor racial groups in Sri Lanka, establishing the allele/haplotype frequency for the candidate genes in those volunteers and in 80 white Caucasian population volunteers, and comparing their allele/haplotype frequencies; recruitment of 180 Sinhalese women with pre-eclampsia and 180 normotensive pregnant Sinhalese women, establishing the allele/haplotype frequencies of the candidate genes in these women and in 74 white Caucasian women with pre-eclampsia and 81 normotensive pregnant white Caucasian women, comparing the pre-eclampsia phenotype of the Sinhalese with that of the white Caucasians, examining the association of the candidate genes with pre-eclampsia, and examining the association of the candidate genes with quantitative traits such as birth weight and blood pressure in normotensive pregnant women; and examining the functional effects of polymorphisms in the angiotensinogen gene on gene expression. The phenotyping results of the Sinhalese women reflect the severe morbidity associated with pre-eclampsia elsewhere, and highlight the severe perinatal mortality associated with pre-eclampsia in the Sinhalese. The population genetic results show considerable similarity between allele/haplotype frequencies of the Sri Lankan racial groups and considerable variation between them and the white Caucasians. The EGF gene was associated with pre-eclampsia in the Sinhalese and with the weight of babies at birth in both the Sinhalese and the white Caucasians. The TGFA, ANG and MTHFR genes were not associated with either pre-eclampsia or any quantitative trait. The angiotensinogen reporter gene expression studies revealed the possible existence of a repressor element in the 3' untranslated region of the angiotensinogen gene, but this finding needs confirmation by further investigations.

Background: Venous thromboembolism (VTE) in one of the leading causes of maternal morbidity and mortality in high income countries. However there is a surprising shortage of evidence which allows us to accurately predict which women are at high risk which has hindered prevention to date. Therefore the aim of this thesis is to measure the occurrence of and risk factors for VTE during the antepartum and postpartum periods. Methods: Electronic health records from women of childbearing age (15-44 years) were identified from two separate databases; The Health Improvement Network (THIN) between 1995 and 2009 and the Clinical Practice Research Datalink (CPRD) linked to Hospital Episode Statistics (HES) between 1997 and 2010. Five separate studies were then carried out to study the incidence and risk factors for VTE during antepartum and postpartum periods. In studies 1 and 2 I used the THIN database to assess the incidence of and risk factors for VTE during antepartum and postpartum periods separately. Studies 3, 4 and 5 incorporated the CPRD-HES linked data which enabled me to get better ascertainment of VTE and its potential risk factors. Using these data I externally validated my VTE definition which was followed by investigating the impact of non-delivery related hospitalisations on the incidence of antepartum VTE. I also examined the risk factors for postpartum VTE using a conceptual hierarchical analysis approach along with their impact on the timing of VTE during specific periods of postpartum. All results were presented in the form of absolute rates (AR) per 100,000 person-years and incidence rate ratios (IRR) were calculated using Poisson regression with adjustment for relevant covariates. Results: In THIN, there were a total of 1.7 million women of which 280,451 experienced 376,154 pregnancies resulting in live or stillbirths whereas the CPRD-HES linked data contained information on over 240,000 pregnancies among 204,929 women. Overall VTE rates were highest in the first few weeks postpartum. Women in their third trimester of antepartum were at a 5 fold increased risk of first VTE compared to their time outside pregnancy whereas in the first and second trimesters this rate was only marginally higher. However the use of CPRD-HES linked database gave me estimates of VTE risk with better precision in and around pregnancy that were comparable to the existing literature. For my risk factor analysis I found that the strongest risk factor for VTE during the antepartum period was hospitalisation corresponding to a 17-fold increase (IRR=17.7 95%CI=7.7-39.6) compared to time outside hospital. The rate of VTE was also high during the 28 days post-discharge (IRR=5.9; 95%CI=3.5-10.0; AR=646). These factors were not confounded by pregnancy related characteristics and complications, pre-existing medical co-morbidities or demographic or life style related characteristics. I also found that postpartum, women whose pregnancies resulted in stillbirth were at a 6- fold (IRR=6; 95%CI 3.17-14.6; AR=2570) increased risk of VTE. Those with caesarean delivery (elective or emergency), pre-term birth or postpartum haemorrhage had a 2-fold or higher risk of postpartum VTE compared to their respective baseline (AR>600/100,000 person-years). These findings were consistent across both the THIN and CPRD-HES linked data bases with respect women's risk factors for VTE. Finally the risk of VTE remains consistently high up to first six weeks postpartum (>700/100,000 person-years) for pregnancies of women complicated with BMI>30kg/m2 or caesarean delivery whereas risk of VTE was only high in the first three weeks postpartum (>1300/100,000 person-years) In those with pre-term birth or postpartum haemorrhage. Conclusion: I have provided some of the most precise estimates of absolute rates of VTE In and around pregnancy for better understanding of risks. The overall rate of antepartum VTE is substantially increased during non-delivery related hospitalisations and this increase is sustained in the 28 days post-discharge. Postpartum, delivery associated characteristics and complications including, stillbirth, caesarean delivery, BMI>30Kg/m2 postpartum haemorrhage are important risk factors for VTE particularly during the first three weeks postpartum. My analysis provides valuable information to clinicians for better decision making in terms of identifying high risk pregnant and postpartum women who may require some form of thromboprophylaxis.

According to the concept of perinatal programming environmental factors during fetal development and early postnatal life can influence phenotype in later life by modifying organ and tissue development and the epigenetic information of specific genes which, in turn, induce alteration in gene expression. Global nutrient restriction is a well-established intervention to study fetal programming but choline, a micronutrient essential for tissue growth and development, has not been extensively studied. The aim of this thesis is to investigate long term effects of modifications in maternal macro and micronutrient intake on the offsprings‟ appetite regulation and metabolic health. Twin-pregnant sheep were fed to requirements until 110 days of gestation and then randomised to stay on the same diet (R) or be restricted to 60% of caloric requirements (N) until term (~145 days). Offspring were subsequently subject either to a standard early postnatal growth rate as both twins remained with the mother (S) or to an accelerated growth rate resulting when only one twin remained to be mother fed (A). After weaning, offspring were reared in either a lean (L) or an obesogenic environment (O) until 17 months of age. These interventions gave rise to 4 groups: RAO, NAO, NSO and NSL. There were no differences in body weight, composition or adipocyte size with perinatal nutrient restriction but insulin response to a glucose tolerance test was increased in offspring born to N mothers. Measurement of hypothalamic gene expression in the latter offspring suggested a more orexigenic and cortisol-sensitive regulatory phenotype. During lactation, rats were fed a diet that was either choline-devoid (D), or contained a standard amount of choline either as bitartrate (C) or as phosphatidylcholine (PC). After weaning, female offspring were maintained on a standard choline diet until 11 weeks of age. D mothers had a substantial decrease in food intake and offspring were smaller at weaning but had similar glucose tolerance. Adult offsprings‟ brain phospholipid concentrations were reduced, which may suggest changes in brain development, but food intake and hypothalamic protein expression were unchanged. Intake of different forms of choline, i.e. bitartrate versus PC, during lactation had no long term effects on offspring. Both maternal dietary interventions had long term effects on offspring. Sheep developed the most adverse metabolic phenotype when the offspring were subjected to slow growth in late gestation followed by rapid growth and obesity, with the onset of insulin resistance mediated through changes in peripheral tissues. Maternal choline intake during lactation is essential for the health of the offspring as it alters brain composition. In conclusion, both studies produced results which are consistent with the concept of perinatal programming as adult metabolic health was affected in the sheep study and organ development was affected in a long term manner in the rat study.

This thesis examines the effectiveness of a new curriculum for the preparation of midwives. Data were collected over a three year period in seven case study institutions, from women who had their babies in one large maternity unit and from a professional network of experienced midwives whose role is to advise the statutory body regulating midwifery programmes in England. The overall intention of the study was to improve the pre-registration midwifery curriculum locally and influence national policy and guidelines. Action research provided the framework for the study where a multi-method approach was largely qualitative to attempt to capture the context and complexity in which the midwifery education programme operates. The research explores and compares curriculum intentions with the perceived experiences of the curriculum as reported by key stakeholders. The development of a holistic integrated model of a competent midwife provided the framework for discourse on curriculum effectiveness, the design of an assessment matrix and recommendations for curriculum improvement. Overall the three year pre-registration route into midwifery was found to be an effective preparation for contemporary midwifery practice as judged against a model of a competent midwife. However there was evidence to suggest that not all students were equipped to practice competently and confidently in contexts of uncertainty and change in the health service. Factors which emerged as influencing curriculum effectiveness related to: recruitment and selection, curriculum structure, appropriateness and robustness of assessment schemes, the preparation of and support for assessors and the role of the midwife teacher in assessment in practice settings. Diagnosing problems and initiating actions as a collaborative process formed an important part of designing and implementing an ideal curriculum in changing and constrained health and higher education contexts. The need for on-going dialogue, critical reflection and research to facilitate and assess learning more effectively in the caring professions emerged as necessary to ensure only competent practitioners have a licence to practice.

This ethnographic study using participant observation, aimed to explore the issue of informed consent to procedures undertaken during the intrapartum period. It involved recruiting 100 healthy women, who went into labour spontaneously at term, at the point they were admitted to the labour ward. The data collection took place in a large teaching hospital in an East Midlands city from April 1997 until December 1999. The subjects (health professionals and women) were observed throughout the labour until the woman and baby were transferred to the postnatal area. Follow-up interviews were conducted with the woman and midwives, within 24 hours, using a semi-structured format based on the observations. The study revealed that it was difficult to obtain informed consent during labour. Contrary to professional belief, not all women wanted to be fully informed about intrapartum care and procedures, or wanted anything other than a pain free and easy labour that they perceived the western medical-technocratic model of care would offer them. Although the midwives' knowledge of legal and ethical issues concerning consent was variable and limited in the majority of cases, they attempted to empower women to make intrapartum choices. However, this was often constrained by the culture of the labour ward environment and the extent to which they adhered to policies and procedures. In cases where medical intervention became necessary, a minority of midwives felt personally disempowered. The obstetricians and paediatricians observed, appeared to be less effective communicators than anaesthetists, often leaving it to the midwife to explain issues to the woman. It is envisaged that these findings, as well as the stereotypical models of the labouring woman and the attending midwife that developed, and the resulting recommendations, be used in partnership between maternity service and education providers to ensure that health professionals not only have effective communication and interpersonal skills, but also are more conversant with the legal and ethical implications of consent.

Childbirth holds short and long-term physical and psychological effects for women. Yet, numerous investigations into childbirth have overlooked the delicate interrelated psychological and emotional interplay that women experience, in favour of the physical, such as the outcomes of birth, maternal mortality, and the physical skills of healthcare providers. Although quantitative measures derived from these are important to establish and evaluate maternal health, they are not adequate to explain the complexity of the human experience of childbirth. Without this understanding there is inadequate guidance about how to proceed to achieve the Sustainable Development Goals targeting maternal health. The aim of this study was to explore childbirth experiences of women giving birth in Zambia, in order to better understand how they experience and give meaning to the phenomenon. The study was guided by an interpretive phenomenology approach. This type of phenomenology was found to be appropriate because the study sought to understand childbirth within the context of everyday lives of women birthing in Zambia. Purposive sampling was utilised to recruit 50 women aged between 16 and 38 years. The women had birthing experiences that occurred between 2005 and 2011. The birthing experiences were from all the ten provinces of Zambia. Data were collected through in-depth unstructured interviews, which were tape recorded. Data analysis was guided by van Manen’s six steps of analysis. Seven themes namely: 1) Conforming to societal norms, 2) Clash between traditional and contemporary childbirth practices, 3) Being in a dilemma, 4) Loss of dignity, 5) Feeling insecure, 6) Inadequate service provision, and 7) Being there for the woman, emerged from the analysis. Each theme had several sub-themes that provided a clearer picture of how participants experienced the phenomenon. The embodied experiences of participants illuminated the complex context of childbirth, whereby, the phenomenon was experienced in private, behind the closed door of secrecy that encompassed difficulties and issues such as, lack of choice, sub-standard care, discrimination, fear and conflicting information. The findings revealed that there was a need for an attitudinal change in maternity care professionals towards a more caring approach, as well as a parallel need to build agency and autonomy in women. For women, the change needs to be addressed at an individual and societal level, beginning with simple things, such as assertiveness training through to educational opportunities, so that they develop economic independence. Macro-reforms (top-down change) need to be combined with micro-reforms (bottom-up change) to challenge existing discriminatory, oppressive and patriarchal attitudes and practices that impact on women’s birth experiences. Women’s voices need to be heard. Understanding maternal outcomes at a micro level can help inform decisions and influence policy at the larger macro levels of institutions and government. Overlooking this intrinsic level represented an important barrier to utilisation of skilled birth care and constituted a common cause of suffering and human rights violations for birthing women. The key implications for practice pointed to a need for all maternity care stakeholders in Zambia to have an understanding of how women birthing in Zambia experience and give meaning to the childbirth phenomenon. This could start by re-examining current approaches to improving reproductive health, and addressing the contextual factors and community based issues that have been brought to light in this study. In the absence of such an understanding it is difficult to map out interventions that do not infringe on women’s beliefs and practices.

Waterbirth practice has the potential to support a midwifery model of care and yet little is known about how the organisation of care can be changed to improve the use of birthing pools. This action research study focused on a group of midwives working on a labour ward in an English obstetric led maternity unit with 3,800 births and 25 recorded waterbirths per year. Interviews and focus groups with labour ward midwives and managers were employed to identify barriers to birthing pool use and inform the change process. Three problem-solving workshops with labour ward coordinators were organised with the aim of influencing other midwives’ use of birthing pools. Data from a newly developed waterbirth questionnaire and maternity records were used to evaluate change in levels of personal knowledge, waterbirth self-efficacy and social support. Foucauldian discourse analysis and One-Way ANOVA with Tukey post hoc tests were used to analyse qualitative and quantitative data. Fourteen midwives took part in focus groups and seventeen in interviews over four research phases. Interventions, developed by workshop attendees, included improvements to the recording and dissemination of waterbirth and water immersion data, target setting and the appointment of a waterbirth champion. By the end of the study the numbers of waterbirth practitioners, recorded waterbirths and social support increased significantly. Discourse analysis revealed the presence of dominant biomedical and subjugated ‘being with woman’ midwifery discourses. The study is the first to describe midwives’ attitudes to waterbirth practice and attempt to improve the use of hospital birthing pools. The findings illustrate that, by co-opting rather than replacing dominant discourses, it is possible to support the delivery of a midwifery model of care in a medicalised environment. As such this study offers a pragmatic approach to organisational change.