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Abstract The motor neuroscience literature suggests that the central nervous system may encode some motor commands in terms of velocity. In this work, we tackle the question: what consequences would velocity commands produce at the behavioral level? Considering the ubiquitous presence of noise in the neuromusculoskeletal system, we predict that velocity commands affected by stationary noise would produce “random walks”, also known as Brownian processes, in position. Brownian motions are distinctively characterized by a linearly growing variance and a power spectral density that declines in inverse proportion to frequency. This work first shows that these Brownian processes are indeed observed in unbounded motion tasks e.g., rotating a crank. We further predict that such growing variance would still be present, but bounded, in tasks requiring a constant posture e.g., maintaining a static hand position or quietly standing. This hypothesis was also confirmed by experimental observations. A series of descriptive models are investigated to justify the observed behavior. Interestingly, one of the models capable of accounting for all the experimental results must feature forward-path velocity commands corrupted by stationary noise. The results of this work provide behavioral support for the hypothesis that humans plan the motion components of their actions in terms of velocity.

In higher education, many students do not complete their studies within the term allotted. A Dutch university implemented an intervention aimed to reduce this form of academic procrastination. The intervention consisted of three measures: (1) requiring students to acquire all first-year credits within their first year in university, (2) reducing the number of resits, and (3) introducing compensation opportunities for insufficient grades. In this study, we investigated which groups of students (if any) benefited most from this intervention. We divided 29,629 students entering the university between 2009 and 2015 into subgroups based on their gender, ethnic background, and level of achievement during pre-university education. For each subgroup, we determined both first-year completion and three-year bachelor graduation rates, both before and after the introduction of the intervention. It was demonstrated that almost all subgroups profited from the intervention. Particularly students from subgroups that in the past performed less well showed much better first-year completion rates and much lower study delay rates. Dropout rates did not change significantly. For most subgroups, an effect of the intervention was still visible after three years: Three-year graduation rates were higher, although the effect was smaller than completion rates in the first academic year.

Abstract Background This study explores patients’ need for information and support in deciding on esophageal cancer treatment, when experimental active surveillance and standard surgery are both feasible. Methods This psychological companion study was conducted alongside the Dutch SANO‐trial (Surgery As Needed for Oesophageal cancer). In‐depth interviews and questionnaires were used to collect data from patients who declined participation in the trial because they had a strong preference for either active surveillance (n = 20) or standard surgery (n = 20). Data were analyzed using both qualitative and quantitative techniques. Results Patients prefer to receive information directly from their doctors and predominantly rely on this information to make a treatment decision. Other information resources are largely used to confirm their treatment decision. Patients highly value support from their loved ones and appreciate emphatic doctors to actively involve them in the decision‐making process. Overall, patients’ needs for information and support during decision‐making were met. Conclusions The importance of shared decision‐making and the role doctors have in this process is underlined. The role of doctors is essential at the initial phase of decision‐making: Once patients seem to have formed their treatment preference for either active surveillance or surgery, the influence of external resources (including doctors) may be limited.

Objectives To determine whether integrated maternity care is associated with reduced preterm births (PTB) and fewer small-for-gestational-age infants (SGA), and whether its implementation leads to a reduction of secondary care consultations.Design Retrospective study.Setting Integrated maternity care organisation in the southwestern region of the Netherlands.Participants All singleton pregnancies (≥24 weeks) within integrated maternity care organisation Annature between 2015 and 2020.Intervention Implementation of a shared maternity record in primary and secondary care.Methods Data of 20 818 women were derived from patient records and from the Netherlands Perinatal Registry. Intervention was the introduction of integrated maternity care in January 2018. Through multivariate logistic regression and segmented regression analysis we assessed the combined prevalence of SGA and PTB (SGA-PTB) before (2015–2017), and after the intervention (2018–2020). Regional rates were contrasted with nationwide rates (n=782 176).Main outcome measures SGA-PTB prevalence and mean number of secondary care consultations per pregnancy.Results SGA-PTB prevalence declined from 618/3443 (17.9%) in 2015 to 560/3501 (16.0%) in 2017 to 507/3459 (14.7%) in 2020 (p

Abstract Background Neoadjuvant chemoradiotherapy (nCRT) followed by esophagectomy is a standard treatment for potentially curable esophageal cancer. Active surveillance in patients with a clinically complete response (cCR) 12 weeks after nCRT is regarded as possible alternative to standard surgery. The aim of this study is to monitor the safety, adherence and effectiveness of active surveillance in patients outside a randomized trial. Methods This nationwide prospective cohort study aims to accrue operable patients with non-metastatic histologically proven adenocarcinoma or squamous cell carcinoma of the esophagus or esophagogastric junction. Patients receive nCRT and response evaluation consists of upper endoscopy with bite-on-bite biopsies, endoscopic ultrasonography plus fine-needle aspiration of suspicious lymph nodes and 18F-fluorodeoxyglucose positron emission tomography/computed tomography scan. When residue or regrowth of tumor in the absence of distant metastases is detected, surgical resection is advised. Patients with cCR after nCRT are suitable to undergo active surveillance. Patients can consult an independent physician or psychologist to support decision-making. Primary endpoint is the number and severity of adverse events in patients with cCR undergoing active surveillance, defined as complications from response evaluations, delayed surgery and the development of distant metastases. Secondary endpoints include timing and quality of diagnostic modalities, overall survival, progression-free survival, fear of cancer recurrence and decisional regret. Discussion Active surveillance after nCRT may be an alternative to standard surgery in patients with esophageal cancer. Similar to organ-sparing approaches applied in other cancer types, the safety and efficacy of active surveillance needs monitoring before data from randomized trials are available. Trial registration The SANO-2 study has been registered at ClinicalTrials.gov as NCT04886635 (May 14, 2021) – Retrospectively registered.

The purpose of the study reported here was to observe the effects of examination practices on the extent to which university students procrastinate. These examination practices were: (1) limiting the number of resits, (2) compensatory rather than conjunctive decision-making about student progress, and (3) restricting the time available for completing the first bachelor year. Study success in the first academic year (successful completion within one year, delay, or dropout) of 12,432 students entering a Dutch university before the introduction of the new examination practices was compared with that of 17,036 students admitted after its introduction. After the implementation of the new examination practices successful completion increased with 23% and delay decreased with 25%. The data were collected using an interrupted time series design. Three attempts were made to deal with possible threats to its internal validity. (1) Potential confounding variables were demonstrated not to play a role in explaining the effect of the new examination practices. (2) Interrupted time series regression demonstrated that the intervention, not other changes over time, contributed to study success. And (3), extraneous events interfering with the effect of the intervention were shown to be unlikely. In conclusion, the study presented here is the first to demonstrate the effect of examination rules on study delay. The findings indicate that delays, as usually observed in higher education, are not necessarily the result of lack of ability. Nor are they necessarily the effect of some inherent personality disorder.

Abstract Corticotroph macroadenomas are rare but difficult to manage intracranial neoplasms. Mutations in the two Cushing’s disease mutational hotspots USP8 and USP48 are less frequent in corticotroph macroadenomas and invasive tumors. There is evidence that TP53 mutations are not as rare as previously thought in these tumors. The aim of this study was to determine the prevalence of TP53 mutations in corticotroph tumors, with emphasis on macroadenomas, and their possible association with clinical and tumor characteristics. To this end, the entire TP53 coding region was sequenced in 86 functional corticotroph tumors (61 USP8 wild type; 66 macroadenomas) and the clinical characteristics of patients with TP53 mutant tumors were compared with TP53/USP8 wild type and USP8 mutant tumors. We found pathogenic TP53 variants in 9 corticotroph tumors (all macroadenomas and USP8 wild type). TP53 mutant tumors represented 14% of all functional corticotroph macroadenomas and 24% of all invasive tumors, were significantly larger and invasive, and had higher Ki67 indices and Knosp grades compared to wild type tumors. Patients with TP53 mutant tumors had undergone more therapeutic interventions, including radiation and bilateral adrenalectomy. In conclusion, pathogenic TP53 variants are more frequent than expected, representing a relevant amount of functional corticotroph macroadenomas and invasive tumors. TP53 mutations associated with more aggressive tumor features and difficult to manage disease.

Abstract Introduction Malalignment of the Total Ankle Replacement (TAR) has often been postulated as the main reason for the high incidence of TAR failure. As the ankle joint has a small contact area, stresses are typically high, and malalignment may lead to non-homogeneous stress distributions, including stress peaks that may initiate failure. This study aims to elucidate the effect of TAR malalignment on the contact stresses on the bone-implant interface, thereby gaining more understanding of the potential role of malalignment in TAR failure. Methods Finite Element (FE) models of the neutrally aligned as well as malaligned CCI (Ceramic Coated Implant) Evolution TAR implant (Van Straten Medical) were developed. The CCI components were virtually inserted in a generic three-dimensional (3D) reconstruction of the tibia and talus. The tibial and talar TAR components were placed in neutral alignment and in 5° and 10° varus, valgus, anterior and posterior malalignment. Loading conditions of the terminal stance phase of the gait cycle were applied. Peak contact pressure and shear stress at the bone-implant interface were simulated and stress distributions on the bone-implant interface were visualized. Results In the neutral position, a peak contact pressure and shear stress of respectively 98.4 MPa and 31.9 MPa were found on the tibial bone-implant interface. For the talar bone-implant interface, this was respectively 68.2 MPa and 39.0 MPa. TAR malalignment increases peak contact pressure and shear stress on the bone-implant interface. The highest peak contact pressure of 177 MPa was found for the 10° valgus malaligned tibial component, and the highest shear stress of 98.5 MPa was found for the 10° posterior malaligned talar model. High contact stresses were mainly located at the edges of the bone-implant interface and the fixation pegs of the talar component. Conclusions The current study demonstrates that TAR malalignment leads to increased peak stresses. High peak stresses could contribute to bone damage and subsequently reduced implant fixation, micromotion, and loosening. Further research is needed to investigate the relationship between increased contact stresses at the bone-implant interface and TAR failure.

Abstract Background Malalignment is often postulated as an important reason for the high failure rate of total ankle replacements (TARs). The correlation between TAR malalignment and clinical outcome, however, is not fully understood. Improving and expanding radiographic TAR alignment measurements in the clinic might lead to a better insight into the correlation between malalignment and the clinical outcome. This study aims to develop and validate a tool to semi‐automatic measure TAR alignment, and to improve alignment measurements on radiographs in the clinic. Methods A tool to semi‐automatically measure TAR alignment on anteroposterior and lateral radiographs was developed in MATLAB. Using the principle of edge contouring and the perpendicular relationship between the anteroposterior and lateral radiographs, the exact configuration of the TAR components can be found. Two observers validated the tool by measuring TAR alignment of ten patients using the tool. The Intraclass Coefficient (ICC) was calculated to assess the reliability of the developed method. The results obtained by the tool were compared to clinical results during radiographic follow‐up in the past, and the accuracy of both methods was calculated using three‐dimensional CT data. Results The tool showed an accuracy of 76% compared to 71% for the method used during follow‐up. ICC values were 0.94 (p

Abstract Background Total ankle arthroplasty is increasingly used as a treatment for end stage ankle arthropathy. The aim of this study was to report the mid‐term clinical function and survival results of Ceramic Coated Implant (CCI) ankle replacements and assess the association between the alignment of the CCI total ankle replacements and early functional outcome and complication incidence. Methods Data of 61 patients, who received 65 CCI implants between 2010 and 2016, were obtained from a prospectively documented database. Mean follow‐up time was 85.2 months (range 27–99 months). Clinical function was assessed with AOFAS questionnaire and passive range of motion (ROM). Survival analysis and elaborate radiographic analysis was performed. Furthermore, complications and reoperations were recorded for all patients. Results Progression in ROM was most seen in the first 10 months from 21.8 degrees of passive range of motion preoperative to 27.6 degrees postoperative (p

Background: Adrenocortical carcinoma is a rare malignancy with a poor prognosis. We hypothesized that patients with adrenocortical carcinoma are at high risk for venous thromboembolism, given the numerous risk factors such as malignancy, abdominal surgery, immobility and hormonal excess. The aim of this study was to determine retrospectively the incidence of venous thromboembolisms after surgical treatment in patients with adrenocortical carcinoma. Materials and methods: A retrospective study was performed, collecting data from all patients diagnosed with adrenocortical carcinoma from 2003 to 2018 at the Radboud University Medical Centre, The Netherlands. Results: In 34 patients, eight postoperative venous thromboembolisms, all pulmonary embolisms, were diagnosed in the first 6 months after adrenalect omy (23.5%). In addition, one patient developed pulmonary embolism just prior to surgery and one patient 7 years after surgery. Five of the eight patients with postoperative venous thromboembolisms presented with symptomatic pulmonary embolism whereas the other three pulmonary embolisms were incidentally found on regular follow up CT scans. Seven of the eight venous thromboembolisms occurred within 10 weeks after surgery. Seven of the eight patients had advanced stage adrenocortical carcinoma and four patients already received low-molecular weight heparin during the development of the venous thromboembolism. There was one case of fatal pulmonary embolism in a patient with a cortisol producing tumor with pulmonary metastases, despite the use of a therapeutic dose thromboprophylaxis. Conclusion: Patients with adrenocortical carcinoma are at high risk of developing postoperative venous thromboembolisms. Prolonged postoperative thromboprophylaxis could be considered in these patients.

Objective: Acromegaly is characterized by an excess of growth hormone (GH) and insulin-like growth factor 1 (IGF1). Cardiovascular disease (CVD) risk factors are common in acromegaly and often persist after treatment. Both acute and long-lasting pro-inflammatory effects have been attributed to IGF1. Therefore, we hypothesized that inflammation persists in treated acromegaly and may contribute t o CVD risk. Methods: In this cross-sectional study, we assessed cardiovascular structure and function, and inflammatory parameters in treated acromegaly patients. Immu ne cell populations and inflammatory markers were assessed in peripheral blood from 71 treated acromegaly patients (with controlled or uncontrolled disease) and 41 matched controls. Whole blood (WB) was stimulated with Toll-like receptor ligands. In a subgroup of 21 controls and 33 patients with controlled disease, vascular ultrasound measurements were performed. Results: Leukocyte counts were lower in patients with controlled acromegaly compared to patients with uncontrolled acromegaly and controls. Circulating IL18 concentrations were lower in patients; concentrations of other inflammatory med iators were comparable with controls. In stimulated WB, cytokine production was skewed toward inflammation in patients, most pronounced in those with uncontro lled disease. Vascular measurements in controlled patients showed endothelial dysfunction as indicated by a lower flow-mediated dilatation/nitroglycerine-mediated dilatation ratio. Surprisingly, pulse wave analysis and pulse wave velocity, both markers of endothelial dysfunction, were lower in patients, whereas intima-media thickness did not differ. Conclusions: Despite treatment, acromegaly patients display persistent infla mmatory changes and endothelial dysfunction, which may contribute to CVD risk and development of CVD.

Abstract Background Job satisfaction is generally considered to be an important element of work quality and workplace relations. Little is known about levels of job satisfaction among hospital and primary-care midwives in the Netherlands. Proposed changes to the maternity care system in the Netherlands should consider how the working conditions of midwives affect their job satisfaction. Aim We aimed to measure and compare job satisfaction among hospital and primary-care midwives in the Netherlands. Methods Online survey of all practising midwives in the Netherlands using a validated measure of job satisfaction (the Leiden Quality of Work Questionnaire) to analyze the attitudes of hospital and primary-care midwives about their work. Descriptive and inferential statistics were used to assess differences between the two groups. Results Approximately one in six of all practising midwives in the Netherlands responded to our survey (hospital midwives n = 103, primary-care midwives n = 405). All midwives in our survey were satisfied with their work (n = 508). However, significant differences emerged between hospital and primary-care midwives in terms of what was most important to them in relation to their job satisfaction. For hospital midwives, the most significant domains were: working hours per week, workplace agreements, and total years of experience. For primary-care midwives, social support at work, work demands, job autonomy, and the influence of work on their private life were most significant. Conclusion Although midwives were generally satisfied, differences emerged in the key predictors of job satisfaction between hospital and primary-care midwives. These differences could be of importance when planning workforce needs and should be taken into consideration by policymakers in the Netherlands and elsewhere when planning new models of care.

Objective: To develop a primary aldosteronism (PA) disease-specific Health -Related Quality of Life (HRQoL) questionnaire. Methods: We included newly diagnosed patients with PA (n = 26), and patients with PA after adrenalectomy (n = 25) or treated with mineralocorticoid receptor antagonists (n = 25). According to the guidelines for developing HRQoL questionnaires from the European Organization for Research and Treatment of Cancer (EORTC): Phase I: systematic literature review followed by focus group meetings with patients (n = 13) resulting in a list of 94 HRQoL issues. Relevance of issues was rated by 18 other patients and by health care professionals (n = 15), resulting in 30 remaining issues. Phase II: selected issues were converted into questions. Phase III: the provisional questionnaire was pre-tested by a third group of patients (n = 45) who also completed the EORTC core Quality of Life questionnaire (QLQ-C30). Psychometric testing resulted in a final selection of questions with their scale structure. Results: After the collection and selection of HRQoL issues a provisional questionnaire consisting of 30 items was formed. Of these items, 26 could be assigned to one of the four scales ‘physical and mental fatigue’, ‘anxiety and stress’, ‘fluid balance’ and ‘other complaints’ cumulatively accounting for 68% of variation in all items. All scales had good reliability and validity. There was a significant correlation of all four scales with the QLQ-C30 in most cases. Conclusions: We developed the first PA-specific HRQoL questionnaire (PA-QoL) using standard, methodologically proven guidelines. After completion of the final validation (phase IV, international field testing), the questionnaire can be implemented into clinical practice.

Abstract Background Conditioning of physiological responses can be achieved by repeatedly pairing a previously neutral conditioned stimulus with the administration of a pharmacologically salient unconditioned stimulus. This type of conditioning has been effective for specific immune and endocrine responses, but results with regard to conditioning of cortisol, a key stress-regulatory parameter, are currently unclear. This paper describes a pharmacological conditioning design, optimized for the examination of effects of cortisol conditioning under both basal conditions and in response to stress. Methods A double-blind randomized controlled conditioning paradigm aimed at conditioning of cortisol is conducted in 48 healthy female volunteers. During the acquisition phase, a gustatory stimulus (conditioned stimulus) is paired with hydrocortisone (100 mg, capsulated, unconditioned stimulus) three times before being administered together with placebo during three evocation sessions. To investigate possible effects of cortisol conditioning in response to stress, participants are exposed to the Trier Social Stress Test during the third evocation session. Primary outcome measure of this study is the mean area under the curve of salivary cortisol during the first two evocation sessions. As secondary outcomes, self-reported affect and stress as well as alpha-amylase are investigated. A pilot study was conducted to ensure that this design is feasible to be used in a larger study. Discussion This study design provides an innovative opportunity to examine the conditioning of cortisol under basal conditions and in response to stress. Also, the possible effect of cortisol conditioning on secondary outcomes of self-reported affect and alpha-amylase can be investigated. If cortisol could successfully be conditioned, this would be of conceptual relevance, showing that hypothalamic pituitary adrenal (HPA) axis regulation can be influenced by associative learning processes. Eventually, this could also have important clinical implications for understanding and treating stress-related disorders in which HPA axis dysregulation might play a role. Trial registration Nederlands Trial Register, NTR4651. Registered on 29 July 2014

Individuals with orofacial clefting (OFC) have a higher prevalence of tooth agenesis (TA) overall. Neither the precise etiology of TA, nor whether TA occurs in patterns that differ by gender or cleft type is yet known. This meta-analysis aims to identify the spectrum of tooth agenesis patterns in subjects with non-syndromic OFC and controls using the Tooth Agenesis Code (TAC) program. An indexed search of databases (PubMed, EMBASE, and CINAHL) along with cross-referencing and hand searches were completed from May to June 2019 and re-run in February 2022. Additionally, unpublished TAC data from 914 individuals with OFC and 932 controls were included. TAC pattern frequencies per study were analyzed using a random effects meta-analysis model. A thorough review of 45 records retrieved resulted in 4 articles meeting eligibility criteria, comprising 2182 subjects with OFC and 3171 controls. No TA (0.0.0.0) was seen in 51% of OFC cases and 97% of controls. TAC patterns 0.2.0.0, 2.0.0.0, and 2.2.0.0 indicating uni- or bi-lateral missing upper laterals, and 16.0.0.0 indicating missing upper right second premolar, were more common in subjects with OFC. Subjects with OFC have unique TA patterns and defining these patterns will help increase our understanding of the complex etiology underlying TA.

Objective: To develop a prediction model to confirm or exclude primary aldosteronism (PA) in patients with an inconclusive salt loading test (SLT). Context: Diagnosis in patients with a suspicion of PA can be confirmed using an SLT. In case of inconclusive test results the decision about how to manage the patient is usually based on contextual clinical data. Design: We included a retrospective cohort of 276 patients in the final analysis. Methods: All patients underwent an SLT between 2005 and 2016 in our university medical center. The SLT was inconclusive (post-infusion aldosterone levels 140–280 pmol/L) in 115 patients. An expert panel then used contextual clinical data to diagnose PA in 45 of them. Together with 101 patients with a positive SLT this resulted in a total of 146 patients with PA. A total of 11 variables were used in a multivariable logistic regression analysis. We assessed internal validity by bootstrapping techniques. Results: The following variables were independently associated with PA: more intense potassium supplementation, lower plasma potassium concentration, lower plasma renin concentration before SLT and higher plasma aldosterone concentration after SLT. The resulting prediction model had a sensitivity of 84.4% and a specificity of 94.3% in patients with an inconclusive SLT. The positive and negative predictive values were 90.5 and 90.4%, respectively. Conclusions: We developed a prediction model for the diagnosis of PA in patients with an inconclusive SLT that results in a diagnosis that was in high agreement with that of an expert panel.

Mechanical forces exerted on tendons during locomotion cannot be readily measured without invasive methods. Here, the authors develop a non-invasive wearable device to track tendon loads by measuring shear wave propagation speed, and demonstrate its use during dynamic human movements.

Humans substantially outperform robotic systems in tasks that require physical interaction, despite seemingly inferior muscle bandwidth and slow neural information transmission. The control strategies that enable this performance remain poorly understood. To bridge that gap, this study examined kinematically constrained motion as an intermediate step between the widely studied unconstrained motions and sparsely studied physical interactions. Subjects turned a horizontal planar crank in two directions (clockwise and counterclockwise) at three constant target speeds (fast, medium, and very slow) as instructed via visual display. With the hand constrained to move in a circle, nonzero forces against the constraint were measured. This experiment exposed two observations that could not result from mechanics alone but may be attributed to neural control composed of dynamic primitives. A plausible mathematical model of interactive dynamics (mechanical impedance) was assumed and used to "subtract" peripheral neuromechanics. This method revealed a summary of the underlying neural control in terms of motion, a zero-force trajectory. The estimated zero-force trajectories were approximately elliptical and their orientation differed significantly with turning direction; that is consistent with control using oscillations to generate an elliptical zero-force trajectory. However, for periods longer than 2-5 s, motion can no longer be perceived or executed as periodic. Instead, it decomposes into a sequence of submovements, manifesting as increased variability. These quantifiable performance limitations support the hypothesis that humans simplify this constrained-motion task by exploiting at least three primitive dynamic actions: oscillations, submovements, and mechanical impedance. [ABSTRACT FROM AUTHOR]

Abstract Background Birth centres are described as settings where women with uncomplicated pregnancies can give birth in a home-like environment assisted by midwives and maternity care assistants. If complications arise or threaten, the woman is referred to a maternity unit of a hospital where an obstetrician will take over responsibility. In the last decade, a number of new birth centres have been established in the Netherlands, based on the assumption that birth centres provide better quality of care since they offer a better opportunity for more integrated care than the existing system with independent primary and secondary care providers. At present, there is no evidence for this assumption. The Dutch Birth Centre Study is designed to present evidence-based recommendations for organization and functioning of future birth centres in the Netherlands. A necessary first step in this evaluation is the development of indicators for measuring the quality of the care delivered in birth centres in the Netherlands. The aim of this study is to identify a comprehensive set of structure and process indicators to assess quality of birth centre care. Methods We used mixed methods to develop a set of structure and process quality indicators for evaluating birth centre care. Beginning with a literature review, we developed an exhaustive list of determinants. We then used a Delphi study to narrow this list, calling on experts to rate the determinants for relevance and feasibility. A multidisciplinary expert panel of 63 experts, directly or indirectly involved with birth centre care, was invited to participate. Results A panel of 42 experts completed two Delphi rounds rating determinants of the quality of birth centre care based on their relevance (to the setting) and feasibility (of use). A set of 30 determinants for structure and process quality indicators was identified to assess the quality of birth centre care in the Netherlands. Conclusions We identified 30 determinants for structure and process quality indicators concerning birth centre care. This set will be validated during the evaluation of birth centres in the Dutch Birth Centre Study.

Abstract Background During the last decade, a rapid increase of birth locations for low-risk births, other than conventional obstetric units, has been seen in the Netherlands. Internationally some of such locations are called birth centres. The varying international definitions for birth centres are not directly applicable for use within the Dutch obstetric system. A standard definition for a birth centre in the Netherlands is lacking. This study aimed to develop a definition of birth centres for use in the Netherlands, to identify these centres and to describe their characteristics. Methods International definitions of birth centres were analysed to find common descriptions. In July 2013 the Dutch Birth Centre Questionnaire was sent to 46 selected Dutch birth locations that might qualify as birth centre. Questions included: location, reason for establishment, women served, philosophies, facilities that support physiological birth, hotel-facilities, management, environment and transfer procedures in case of referral. Birth centres were visited to confirm the findings from the Dutch Birth Centre Questionnaire and to measure distance and time in case of referral to obstetric care. Results From all 46 birth locations the questionnaires were received. Based on this information a Dutch definition of a birth centre was constructed. This definition reads: “Birth centres are midwifery-managed locations that offer care to low risk women during labour and birth. They have a homelike environment and provide facilities to support physiological birth. Community midwives take primary professional responsibility for care. In case of referral the obstetric caregiver takes over the professional responsibility of care.” Of the 46 selected birth locations 23 fulfilled this definition. Three types of birth centres were distinguished based on their location in relation to the nearest obstetric unit: freestanding (n = 3), alongside (n = 14) and on-site (n = 6). Transfer in case of referral was necessary for all freestanding and alongside birth centres. Birth centres varied in their reason for establishment and their characteristics. Conclusions Twenty-three Dutch birth centres were identified and divided into three different types based on location according to the situation in September 2013. Birth centres differed in their reason for establishment, facilities, philosophies, staffing and service delivery.

Abstract Background The goal of integrated care is to offer a continuum of care that crosses the boundaries of public health, primary, secondary, and tertiary care. Integrated care is increasingly promoted for people with complex needs and has also recently been promoted in maternity care systems to improve the quality of care. Especially when located near an obstetric unit, birth centres are considered to be ideal settings for the realization of integrated care. At present, however, we know very little about the degree of integration in these centres and we do not know if increased levels of integration improve the quality of the care delivered. The Dutch Birth Centre Study is designed to evaluate birth centres and their contribution to the Dutch maternity care system. The aim of this particular sub-study is to classify birth centres in clusters with similar characteristics based on integration profiles, to support the evaluation of birth centre care. Methods This study is based on the Rainbow Model of Integrated Care. We used a survey followed by qualitative interviews in 23 birth centres in the Netherlands to determine which integration profiles can be distinguished and to describe their discriminating characteristics. Cluster analysis was used to classify the birth centres. Results Birth centres were classified into three clusters: 1)“Mono-disciplinary-oriented birth centres” (n = 10): which are mainly owned by primary care organizations and established as physical facilities to provide an alternative birthplace for low risk births; 2) “Multi-disciplinary-oriented birth centres” (n = 6): which are mainly multi-disciplinary oriented and can be regarded as facilities to give birth, with a focus on integrated birth care; 3) “Mixed Cluster of birth centres” (n = 7): which have a range of organizational forms that differentiate them from centres in the other clusters. Conclusion We identified a recognizable classification, with similar characteristics between birth centres in the clusters. The results of this study can be used to relate integration profiles of birth centres to quality of care, costs, and perinatal outcomes. This assessment makes it possible to develop recommendations with regard to the type and degree of integration of Dutch birth centres in the future.