The main topic of this PhD thesis is the Arakelov ray class group of a number field, an algebraic object that contains both the ideal class group structure and the unit group structure. The main... Show moreThe main topic of this PhD thesis is the Arakelov ray class group of a number field, an algebraic object that contains both the ideal class group structure and the unit group structure. The main result consists of the fact that certain specific random walks on the Arakelov ray class group result in a target point that is uniformly distributed on this group, under the assumption of an extended version of the Riemann Hypothesis. Almost all other results of this work are consequences of this fact. Show less
Wit, L. de; Rademaker, D.; Voormolen, D.N.; Akerboom, B.M.C.; Kiewiet-Kemper, R.M.; Soeters, M.R.; ... ; Rijn, B.B. van 2019
Introduction In women with gestational diabetes mellitus (GDM) requiring pharmacotherapy, insulin was the established first-line treatment. More recently, oral glucose lowering drugs (OGLDs) have... Show moreIntroduction In women with gestational diabetes mellitus (GDM) requiring pharmacotherapy, insulin was the established first-line treatment. More recently, oral glucose lowering drugs (OGLDs) have gained popularity as a patient-friendly, less expensive and safe alternative. Monotherapy with metformin or glibenclamide (glyburide) is incorporated in several international guidelines. In women who do not reach sufficient glucose control with OGLD monotherapy, usually insulin is added, either with or without continuation of OGLDs. No reliable data from clinical trials, however, are available on the effectiveness of a treatment strategy using all three agents, metformin, glibenclamide and insulin, in a stepwise approach, compared with insulin-only therapy for improving pregnancy outcomes. In this trial, we aim to assess the clinical effectiveness, cost-effectiveness and patient experience of a stepwise combined OGLD treatment protocol, compared with conventional insulin-based therapy for GDM.Methods The SUGAR-DIP trial is an open-label, multicentre randomised controlled non-inferiority trial. Participants are women with GDM who do not reach target glycaemic control with modification of diet, between 16 and 34 weeks of gestation. Participants will be randomised to either treatment with OGLDs, starting with metformin and supplemented as needed with glibenclamide, or randomised to treatment with insulin. In women who do not reach target glycaemic control with combined metformin and glibenclamide, glibenclamide will be substituted with insulin, while continuing metformin. The primary outcome will be the incidence of large-for-gestational-age infants (birth weight >90th percentile). Secondary outcome measures are maternal diabetes-related endpoints, obstetric complications, neonatal complications and cost-effectiveness analysis. Outcomes will be analysed according to the intention-to-treat principle.Ethics and dissemination The study protocol was approved by the Ethics Committee of the Utrecht University Medical Centre. Approval by the boards of management for all participating hospitals will be obtained. Trial results will be submitted for publication in peer-reviewed journals.Trial registration number NTR6134; Pre-results. Show less
Overwater, E.; Floor, K.; Beek, D. van; Boer, K. de; Dijk, T. van; Hilhorst-Hofstee, Y.; ... ; Maugeri, A. 2017
Objective To compare the effect of induction of labour with a policy of expectant monitoring for intrauterine growth restriction near term. Design Multicentre randomised equivalence trial (the... Show moreObjective To compare the effect of induction of labour with a policy of expectant monitoring for intrauterine growth restriction near term. Design Multicentre randomised equivalence trial (the Disproportionate Intrauterine Growth Intervention Trial At Term (DIGITAT)). Setting Eight academic and 44 non-academic hospitals in the Netherlands between November 2004 and November 2008. Participants Pregnant women who had a singleton pregnancy beyond 36+0 weeks' gestation with suspected intrauterine growth restriction. Interventions Induction of labour or expectant monitoring. Main outcome measures The primary outcome was a composite measure of adverse neonatal outcome, defined as death before hospital discharge, five minute Apgar score of less than 7, umbilical artery pH of less than 7.05, or admission to the intensive care unit. Operative delivery (vaginal instrumental delivery or caesarean section) was a secondary outcome. Analysis was by intention to treat, with confidence intervals calculated for the differences in percentages or means. Results 321 pregnant women were randomly allocated to induction and 329 to expectant monitoring. Induction group infants were delivered 10 days earlier (mean difference -9.9 days, 95% CI -11.3 to -8.6) and weighed 130 g less (mean difference -130 g, 95% CI -188 g to -71 g) than babies in the expectant monitoring group. A total of 17 (5.3%) infants in the induction group experienced the composite adverse neonatal outcome, compared with 20 (61%) in the expectant monitoring group (difference -0.8%, 95% CI -4.3% to 3.2%). Caesarean sections were performed on 45 (14.0%) mothers in the induction group and 45 (13.7%) in the expectant monitoring group (difference 0.3%, 95% CI -5.0% to 5.6%). Conclusions In women with suspected intrauterine growth restriction at term, we found no important differences in adverse outcomes between induction of labour and expectant monitoring. Patients who are keen on non-intervention can safely choose expectant management with intensive maternal and fetal monitoring; however, it is rational to choose induction to prevent possible neonatal morbidity and stillbirth. Show less
Schutte, J.M.; Steegers, E.A.P.; Schuitemaker, N.W.E.; Santema, J.G.; Boer, K. de; Pel, M.; ... ; Netherlands Maternal Mortality Com 2010
Objective To assess causes, trends and substandard care factors in maternal mortality in the Netherlands. Design Confidential enquiry into the causes of maternal mortality. Setting Nationwide in... Show moreObjective To assess causes, trends and substandard care factors in maternal mortality in the Netherlands. Design Confidential enquiry into the causes of maternal mortality. Setting Nationwide in the Netherlands. Population 2,557,208 live births. Methods Data analysis of all maternal deaths in the period 1993-2005. Main outcome measures Maternal mortality. Results The overall maternal mortality ratio was 12.1 per 100 000 live births, which was a statistically significant rise compared with the maternal mortality ratio of 9.7 in the period 1983-1992 (OR 1.2, 95% CI 1.0-1.5). The most frequent direct causes were (pre-) eclampsia, thromboembolism, sudden death in pregnancy, sepsis, obstetric haemorrhage and amniotic fluid embolism. The number of indirect deaths also increased, mainly caused by an increase in cardiovascular disorders (OR 2.5, 95% CI 1.4-4.6). Women younger than 20 years and older than 45 years, those with high parity or from nonwestern immigrant populations were at higher risk. Most substandard care was found in women with pre-eclampsia (91%) and in immigrant populations (62%). Conclusions Maternal mortality in the Netherlands has increased since 1983-1992. Pre-eclampsia remains the number one cause. Groups at higher risk for complications during pregnancy should be better identified early in pregnancy or before conception, in order to receive preconception advice and more frequent antenatal visits. There is an urgent need for the better education of women and professionals concerning the danger signs, and for the training of professionals in order to improve maternal health care. Show less
