Impact of female obesity and assisted reproduction on uncomplicated pregnancies and healthy births: a study of 428 336 births in Flanders.

STUDY QUESTION: What is the impact of BMI on uncomplicated pregnancies and healthy births in women who did or did not have medically assisted reproduction (MAR, i.e. ART or hormonal stimulation without manipulation of eggs or embryos) in the Flanders region (Belgium)? SUMMARY ANSWER: Women with a higher BMI who use MAR are at the highest risk of pregnancy and birth complications. WHAT WE KNOW ALREADY: Medically assisted reproduction (MAR) is used increasingly worldwide and is associated with increased risk of adverse perinatal outcomes. Obesity is also increasing globally and obese women are more likely to seek MAR since obesity is associated with infertility. When obese women undergo MAR, the risk of adverse outcomes may be enhanced but it is not clear to what extent. STUDY DESIGN, SIZE, DURATION: We conducted a registry-based study using the data from the Study Centre for Perinatal epidemiology database for years 2009-2015, region of Flanders, Belgium. This included 428 336 women. PARTICIPANTS/MATERIALS, SETTING, METHODS: The average age was 30.0 years (SD 4.78), 194 061 (45.31%) were nulliparous, and 6.3% (n = 26 971) conceived with MAR. We examined the association of BMI and MAR with the following composite primary outcomes: 'uncomplicated pregnancy and birth' and 'healthy baby'. We conducted Poisson regression and adjusted for maternal age, parity, gestational weight gain, smoking and previous caesarean section. MAIN RESULTS AND THE ROLE OF CHANCE: In our study, 36.80% (n = 157 623) of women had an uncomplicated pregnancy and birth according to the definition used. The predicted probability of having an uncomplicated pregnancy and birth for women with a BMI of 25 kg/m2 who conceived spontaneously was 0.33 (0.32 to 0.35), while it was 0.28 (0.24 to 0.32) for women who used hormonal stimulation and 0.26 (0.22 to 0.29) for women who used IVF/ICSI. This probability reduced with increasing BMI category for both MAR and non-MAR users. For women with a BMI of 30 kg/m2, the predicted probability of having an uncomplicated pregnancy and birth was 0.28 (0.26 to 0.30) for women who conceived spontaneously, and 0.22 (0.16 to 0.29) and 0.20 (0.14 to 0.26) for women who used hormonal stimulation only or IVF/ICSI, respectively. The predicted probability of having a healthy baby for women with a BMI of 25 kg/m2 who conceived spontaneously was 0.92 (0.91 to 0.93), 0.89 (0.87 to 0.92) for women who used hormonal stimulation only and 0.85 (0.84 to 0.87) for women who used IVF/ICSI. LIMITATIONS, REASONS FOR CAUTION: The database did not include data on socio-economic status, pre-pregnancy morbidities and paternal BMI. Subsequently, we could not adjust for these factors in the analysis. WIDER IMPLICATIONS OF THE FINDINGS: Obese women who use MAR are at the highest risk of pregnancy and birth complications. This increase in interventions also has cost and resource implications which is relevant for funding policies. Weight loss interventions prior to MAR seem plausible but their (cost-) effectiveness needs urgent investigation. STUDY FUNDING/COMPETING INTEREST(S): F.W. received an Erasmus Plus training grant to visit A.B., L.A. and R.D. and conducted this study during this visit. The authors have no competing interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Transport and accumulation of plasma generated species in aqueous solution.

The interaction between cold atmospheric pressure plasma and liquids is receiving increasing attention for various applications. In particular, the use of plasma-treated liquids (PTL) for biomedical applications is of growing importance, in particular for sterilization and cancer treatment. However, insight into the underlying mechanisms of plasma-liquid interactions is still scarce. Here, we present a 2D fluid dynamics model for the interaction between a plasma jet and liquid water. Our results indicate that the formed reactive species originate from either the gas phase (with further solvation) or are formed at the liquid interface. A clear increase in the aqueous density of H2O2, HNO2/NO2- and NO3- is observed as a function of time, while the densities of O3, HO2/O2- and ONOOH/ONOO- are found to quickly reach a maximum due to chemical reactions in solution. The trends observed in our model correlate well with experimental observations from the literature.

Combining experimental and modelling approaches to study the sources of reactive species induced in water by the COST RF plasma jet.

The vast biomedical potential of cold atmospheric pressure plasmas (CAPs) is governed by the formation of reactive species. These biologically active species are formed upon the interaction of CAPs with the surroundings. In biological milieu, water plays an essential role. The development of biomedical CAPs thus requires understanding of the sources of the reactive species in aqueous media exposed to the plasma. This is especially important in case of the COST RF plasma jet, which is developed as a reference microplasma system. In this work, we investigated the formation of the OH radicals, H atoms and H2O2 in aqueous solutions exposed to the COST plasma jet. This was done by combining experimental and modelling approaches. The liquid phase species were analysed using UV-Vis spectroscopy and spin trapping with hydrogen isotopes and electron paramagnetic resonance (EPR) spectroscopy. The discrimination between the species formed from the liquid phase and the gas phase molecules was performed by EPR and 1H-NMR analyses of the liquid samples. The concentrations of the reactive species in the gas phase plasma were obtained using a zero-dimensional (0D) chemical kinetics computational model. A three-dimensional (3D) fluid dynamics model was developed to provide information on the induced humidity in the plasma effluent. The comparison of the experimentally obtained trends for the formation of the species as a function of the feed gas and effluent humidity with the modelling results suggest that all reactive species detected in our system are mostly formed in the gas phase plasma inside the COST jet, with minor amounts arising from the plasma effluent humidity.

Synergistic effect of electric field and lipid oxidation on the permeability of cell membranes.

BACKGROUND: Strong electric fields are known to affect cell membrane permeability, which can be applied for therapeutic purposes, e.g., in cancer therapy. A synergistic enhancement of this effect may be accomplished by the presence of reactive oxygen species (ROS), as generated in cold atmospheric plasmas. Little is known about the synergy between lipid oxidation by ROS and the electric field, nor on how this affects the cell membrane permeability. METHOD: We here conduct molecular dynamics simulations to elucidate the dynamics of the permeation process under the influence of combined lipid oxidation and electroporation. A phospholipid bilayer (PLB), consisting of di-oleoyl-phosphatidylcholine molecules covered with water layers, is used as a model system for the plasma membrane. RESULTS AND CONCLUSIONS: We show how oxidation of the lipids in the PLB leads to an increase of the permeability of the bilayer to ROS, although the permeation free energy barriers still remain relatively high. More importantly, oxidation of the lipids results in a drop of the electric field threshold needed for pore formation (i.e., electroporation) in the PLB. The created pores in the membrane facilitate the penetration of reactive plasma species deep into the cell interior, eventually causing oxidative damage. GENERAL SIGNIFICANCE: This study is of particular interest for plasma medicine, as plasma generates both ROS and electric fields, but it is also of more general interest for applications where strong electric fields and ROS both come into play.

Development of composite outcomes for individual patient data (IPD) meta-analysis on the effects of diet and lifestyle in pregnancy: a Delphi survey.

OBJECTIVE: To develop maternal, fetal, and neonatal composite outcomes relevant to the evaluation of diet and lifestyle interventions in pregnancy by individual patient data (IPD) meta-analysis. DESIGN: Delphi survey. SETTING: The International Weight Management in Pregnancy (i-WIP) collaborative network. Sample Twenty-six researchers from the i-WIP collaborative network from 11 countries. METHODS: A two-generational Delphi survey involving members of the i-WIP collaborative network (26 members in 11 countries) was undertaken to prioritise the individual outcomes for their importance in clinical care. The final components of the composite outcomes were identified using pre-specified criteria. MAIN OUTCOME MEASURES: Composite outcomes considered to be important for the evaluation of the effect of diet and lifestyle in pregnancy. RESULTS: Of the 36 maternal outcomes, nine were prioritised and the following were included in the final composite: pre-eclampsia or pregnancy-induced hypertension, gestational diabetes mellitus (GDM), elective or emergency caesarean section, and preterm delivery. Of the 27 fetal and neonatal outcomes, nine were further evaluated, with the final composite consisting of intrauterine death, small for gestational age, large for gestational age, and admission to a neonatal intensive care unit (NICU). CONCLUSIONS: Our work has identified the components of maternal, fetal, and neonatal composite outcomes required for the assessment of diet and lifestyle interventions in pregnancy by IPD meta-analysis.

Effects of lifestyle intervention in obese pregnant women on gestational weight gain and mental health: a randomized controlled trial.

OBJECTIVE: Lifestyle intervention could help obese pregnant women to limit their weight gain during pregnancy and improve their psychological comfort, but has not yet been evaluated in randomized controlled trials. We evaluated whether a targeted antenatal lifestyle intervention programme for obese pregnant women influences gestational weight gain (GWG) and levels of anxiety or depressed mood. DESIGN AND SUBJECTS: This study used a longitudinal interventional design. Of the 235 eligible obese pregnant women, 205 (mean age (years): 29±4.5; body mass index (BMI, kg m(-)(2)): 34.7±4.6) were randomized to a control group, a brochure group receiving written information on healthy lifestyle and an experimental group receiving an additional four antenatal lifestyle intervention sessions by a midwife trained in motivational lifestyle intervention. Anxiety (State and Trait Anxiety Inventory) and feelings of depression (Edinburgh Depression Scale) were measured during the first, second and third trimesters of pregnancy. Socio-demographical, behavioural, psychological and medical variables were used for controlling and correcting outcome variables. RESULTS: We found a significant reduction of GWG in the brochure (9.5 kg) and lifestyle intervention (10.6 kg) group compared with normal care group (13.5 kg) (P=0.007). Furthermore, levels of anxiety significantly decreased in the lifestyle intervention group and increased in the normal care group during pregnancy (P=0.02); no differences were demonstrated in the brochure group. Pre-pregnancy BMI was positively related to levels of anxiety. Obese pregnant women who stopped smoking recently showed a significant higher GWG (ß=3.04; P=0.01); those with concurrent gestational diabetes mellitus (GDM) (ß=3.54; P=0.03) and those who consumed alcohol on a regular base (ß=3.69; P=0.04) showed significant higher levels of state anxiety. No differences in depressed mood or obstetrical/neonatal outcomes were observed between the three groups. CONCLUSIONS: A targeted lifestyle intervention programme based on the principles of motivational interviewing reduces GWG and levels of anxiety in obese pregnant women.

Defect healing and enhanced nucleation of carbon nanotubes by low-energy ion bombardment.

Structural defects inevitably appear during the nucleation event that determines the structure and properties of single-walled carbon nanotubes. By combining ion bombardment experiments with atomistic simulations we reveal that ion bombardment in a suitable energy range allows these defects to be healed resulting in an enhanced nucleation of the carbon nanotube cap. The enhanced growth of the nanotube cap is explained by a nonthermal ion-induced graphene network restructuring mechanism.

Gas purification by nonthermal plasma: a case study of ethylene.

The destruction of ethylene in a dielectric barrier discharge plasma is investigated by the combination of kinetic modeling and experiments, as a case study for plasma-based gas purification. The influence of the specific energy deposition on the removal efficiency and the selectivity toward CO and CO2 is studied for different concentrations of ethylene. The model allows the identification of the destruction pathway in dry and humid air. The latter is found to be mainly initiated by metastable N2 molecules, but the further destruction steps are dominated by O atoms and OH radicals. Upon increasing air humidity, the removal efficiency drops by ± 15% (from 85% to 70%), but the selectivity toward CO and CO2 stays more or less constant at 60% and 22%, respectively. Beside CO and CO2, we also identified acetylene, formaldehyde, and water as byproducts of the destruction process, with concentrations of 1606 ppm, 15033 ppm, and 185 ppm in humid air (with 20% RH), respectively. Finally, we investigated the byproducts generated by the humid air discharge itself, which are the greenhouse gases O3, N2O, and the toxic gas NO2.

Preconception care.

A good pregnancy outcome is partly determined by a women's preconceptional health and healthy lifestyle. The access to prenatal care is good nowadays but the incidence of congenital malformations, preterm births, low birth weight and maternal mortality has not significantly declined over the years. Although most women of reproductive age have a gynecological examination every two years in Belgium, they are not often counseled before starting a pregnancy. The American College of Obstetricians and Gynecologists (ACOG) states that optimizing a woman's health before and between pregnancies must be an ongoing process. The most vulnerable period for fetal defects is between 4 and 10 weeks of gestation, the period of embryogenesis, meaning that counseling for a healthy life style and reducing high-risk conditions should start preferably before conception.

Effect of plasma-induced oxidative stress on the glycolysis pathway of Escherichia coli.

Antibiotic resistance is one of the world's most urgent public health problems. Due to its antibacterial properties, cold atmospheric plasma (CAP) may serve as an alternative method to antibiotics. It is claimed that oxidative stress caused by CAP is the main reason of bacteria inactivation. In this work, we computationally investigated the effect of plasma-induced oxidation on various glycolysis metabolites, by monitoring the production of the biomass. We observed that in addition to the significant reduction in biomass production, the rate of some reactions has increased. These reactions produce anti-oxidant products, showing the bacterial defense mechanism to escape the oxidative damage. Nevertheless, the simulations show that the plasma-induced oxidation effect is much stronger than the defense mechanism, causing killing of the bacteria.

Oxidation destabilizes toxic amyloid beta peptide aggregation.

The aggregation of insoluble amyloid beta (Aß) peptides in the brain is known to trigger the onset of neurodegenerative diseases, such as Alzheimer's disease. In spite of the massive number of investigations, the underlying mechanisms to destabilize the Aß aggregates are still poorly understood. Some studies indicate the importance of oxidation to destabilize the Aß aggregates. In particular, oxidation induced by cold atmospheric plasma (CAP) has demonstrated promising results in eliminating these toxic aggregates. In this paper, we investigate the effect of oxidation on the stability of an Aß pentamer. By means of molecular dynamics simulations and umbrella sampling, we elucidate the conformational changes of Aß pentamer in the presence of oxidized residues, and we estimate the dissociation free energy of the terminal peptide out of the pentamer form. The calculated dissociation free energy of the terminal peptide is also found to decrease with increasing oxidation. This indicates that Aß pentamer aggregation becomes less favorable upon oxidation. Our study contributes to a better insight in one of the potential mechanisms for inhibition of toxic Aß peptide aggregation, which is considered to be the main culprit to Alzheimer's disease.

Chemical fingerprints of cold physical plasmas - an experimental and computational study using cysteine as tracer compound.

Reactive oxygen and nitrogen species released by cold physical plasma are being proposed as effectors in various clinical conditions connected to inflammatory processes. As these plasmas can be tailored in a wide range, models to compare and control their biochemical footprint are desired to infer on the molecular mechanisms underlying the observed effects and to enable the discrimination between different plasma sources. Here, an improved model to trace short-lived reactive species is presented. Using FTIR, high-resolution mass spectrometry, and molecular dynamics computational simulation, covalent modifications of cysteine treated with different plasmas were deciphered and the respective product pattern used to generate a fingerprint of each plasma source. Such, our experimental model allows a fast and reliable grading of the chemical potential of plasmas used for medical purposes. Major reaction products were identified to be cysteine sulfonic acid, cystine, and cysteine fragments. Less-abundant products, such as oxidized cystine derivatives or S-nitrosylated cysteines, were unique to different plasma sources or operating conditions. The data collected point at hydroxyl radicals, atomic O, and singlet oxygen as major contributing species that enable an impact on cellular thiol groups when applying cold plasma in vitro or in vivo.

Effect of head group and lipid tail oxidation in the cell membrane revealed through integrated simulations and experiments.

We report on multi-level atomistic simulations for the interaction of reactive oxygen species (ROS) with the head groups of the phospholipid bilayer, and the subsequent effect of head group and lipid tail oxidation on the structural and dynamic properties of the cell membrane. Our simulations are validated by experiments using a cold atmospheric plasma as external ROS source. We found that plasma treatment leads to a slight initial rise in membrane rigidity, followed by a strong and persistent increase in fluidity, indicating a drop in lipid order. The latter is also revealed by our simulations. This study is important for cancer treatment by therapies producing (extracellular) ROS, such as plasma treatment. These ROS will interact with the cell membrane, first oxidizing the head groups, followed by the lipid tails. A drop in lipid order might allow them to penetrate into the cell interior (e.g., through pores created due to oxidation of the lipid tails) and cause intracellular oxidative damage, eventually leading to cell death. This work in general elucidates the underlying mechanisms of ROS interaction with the cell membrane at the atomic level.

How the alignment of adsorbed ortho H pairs determines the onset of selective carbon nanotube etching.

Unlocking the enormous technological potential of carbon nanotubes strongly depends on our ability to specifically produce metallic or semiconducting tubes. While selective etching of both has already been demonstrated, the underlying reasons, however, remain elusive as yet. We here present computational and experimental evidence on the operative mechanisms at the atomic scale. We demonstrate that during the adsorption of H atoms and their coalescence, the adsorbed ortho hydrogen pairs on single-walled carbon nanotubes induce higher shear stresses than axial stresses, leading to the elongation of HC-CH bonds as a function of their alignment with the tube chirality vector, which we denote as the γ-angle. As a result, the C-C cleavage occurs more rapidly in nanotubes containing ortho H-pairs with a small γ-angle. This phenomenon can explain the selective etching of small-diameter semiconductor nanotubes with a similar curvature. Both theoretical and experimental results strongly indicate the important role of the γ-angle in the selective etching mechanisms of carbon nanotubes, in addition to the nanotube curvature and metallicity effects and lead us to clearly understand the onset of selective synthesis/removal of CNT-based materials.

Negative ion behavior in single- and dual-frequency plasma etching reactors: particle-in-cell/Monte Carlo collision study.

Particle-in-cell/Monte Carlo simulations are used to simulate the trajectories and energies of randomly sampled F- and CF-(3) ions in capacitively coupled radio-frequency discharges, in order to clarify the movement of the negative ions in the sheaths and plasma in both single- and dual-frequency regimes, as well as in symmetric and asymmetric discharges. In the single-frequency reactor both types of negative ions are confined in the plasma and the main loss mechanism is recombination with positive ions. In the dual-frequency reactor under certain operating conditions when the sheaths are wide and the bulk plasma is narrow the light F- ions move across from one sheath to the other, and they can even be lost at the electrodes. The main loss mechanisms are then electron detachment and absorption at the electrodes. The much heavier CF-(3) ions are still confined in the bulk and represent the major negative charge. In an asymmetric discharge the electric field in the sheath to the smaller (powered) electrode is much stronger than that in the sheath to the grounded electrode. Consequently, the F- ions reach mainly the grounded electrode.

Multiple void formation in plasmas containing multispecies charged grains.

Self-organized separation of charged-dust species in two-dimensional dusty plasmas is studied by means of molecular-dynamics simulation. The multispecies dust grains, interacting through a screened Coulomb potential with a long-range attractive component, are confined by an external quadratic potential and subjected to a radially outward ion drag force. It is found that, in general, the species are spatially separated by bandlike dust-free (or void) regions, and grains of the same species tend to populate a common shell. At large ion drag and/or large plasma screening, a central disklike void as well as concentric bandlike voids separating the different species appear. Because of the outward drag and the attractive component of the dust-dust interaction forces, highly asymmetrical states consisting of species-separated dust clumps can also exist despite the fact that all the forces are either radial or central.

Structure of multispecies charged particles in a quadratic trap.

Multispecies interacting charged particles in a two-dimensional quadratic trap are studied. The ground-state configurations for different particle and species numbers are obtained by molecular dynamics simulation. It is found that particles with similar mass-to-charge ratio tend to populate a common shell, whose location depends on the particle mass-to-charge ratio, and that the greater the latter, the closer are the particles to the center of the trap. This scaling for the ground-state configuration is independent of the total particle and species numbers in the system.

Structural modification of P-glycoprotein induced by OH radicals: Insights from atomistic simulations.

This study reports on the possible effects of OH radical impact on the transmembrane domain 6 of P-glycoprotein, TM6, which plays a crucial role in drug binding in human cells. For the first time, we employ molecular dynamics (MD) simulations based on the self-consistent charge density functional tight binding (SCC-DFTB) method to elucidate the potential sites of fragmentation and mutation in this domain upon impact of OH radicals, and to obtain fundamental information about the underlying reaction mechanisms. Furthermore, we apply non-reactive MD simulations to investigate the long-term effect of this mutation, with possible implications for drug binding. Our simulations indicate that the interaction of OH radicals with TM6 might lead to the breaking of C-C and C-N peptide bonds, which eventually cause fragmentation of TM6. Moreover, according to our simulations, the OH radicals can yield mutation in the aromatic ring of phenylalanine in TM6, which in turn affects its structure. As TM6 plays an important role in the binding of a range of cytotoxic drugs with P-glycoprotein, any changes in its structure are likely to affect the response of the tumor cell in chemotherapy. This is crucial for cancer therapies based on reactive oxygen species, such as plasma treatment.

Mathematical description of a direct current glow discharge in argon.

In order to achieve a better understanding of the glow discharge, different models have been developed for the different species present in the plasma. An overview of the models is given and some typical results are presented. These results include, among others, the densities and energy distributions of the plasma species, the electric field and potential distribution, the contribution of different ionization mechanisms to the ionization of argon and sputtered atoms, the relative contribution of different plasma species to the sputtering process, and the variation of the cathode dark space length and the electrical current as functions of voltage and pressure. The validity of the present models is supported by the good agreement of the calculated current-voltage curves with experiment.

Electron anisotropic scattering in gases: a formula for Monte Carlo simulations.

The purpose of this Brief Report is to point out the mistake in a formula for anisotropic electron scattering, previously published in Phys. Rev. A 41, 1112 (1990), which is widely used in Monte Carlo models of gas discharges. Anisotropic electron scattering is investigated based on the screened Coulomb potential between electrons and neutral atoms. The approach is also applied for electron scattering by nonpolar neutral molecules. Differential cross sections for electron scattering by Ar, N2, and CH4 are constructed on the basis of momentum and integrated cross sections. The formula derived in this paper is useful for Monte Carlo simulations of gas discharges.