Quasi-neutral evolution in populations under small demographic fluctuations.

We study an eco-evolutionary dynamics in finite populations of two haploid asexually reproducing allelic types. We focus on the quasi-neutral case when individual types differ only in their intrinsic birth and death rates but have the same expected lifetime reproductive output. We assume that the population size can fluctuate stochastically. We solve the Kolmogorov forward equation in the population whose size fluctuates only minimally and show that the fixation probability is decreasing with the increasing turnover rate. We also show that when the mutant's turnover is small enough, selection favors the mutant replacing residents. Similarly, when the turnover is high enough, selection opposes the replacement. This basic result has previously been demonstrated numerically for the contact process and shown analytically for the Moran process; the current paper extends this analysis to provide an analytical proof for the contact process. We also demonstrate numerically that our results extend for general fluctuating populations and beyond the quasi-neutral case.

Application of growth rate from kinetic model to calculate stochastic growth of a bacteria population at low contamination level.

Traditional predictive microbiology is not suited for cell growth predictions for low-level contamination, where individual cell heterogeneity becomes apparent. Accordingly, we simulated a stochastic birth process of bacteria population using kinetic parameters. We predicted the variation in behavior of Salmonella enterica serovar Typhimurium cells at low inoculum density. The modeled cells were grown in tryptic soy broth at 25 °C. Kinetic growth parameters were first determined empirically for an initial cell number of 104 cells. Monte Carlo simulation based on the growth kinetics and Poisson distribution for different initial cell numbers predicted the results of 50 replicate growth experiments with the initial cell number of 1, 10, and 64 cells. Indeed, measured behavior of 85% cells fell within the 95% prediction area of the simulation. The calculations link the kinetic and stochastic birth process with Poisson distribution. The developed model can be used to calculate the probability distribution of population size for exposure assessment and for the evaluation of a probability that a pathogen would exceed critical contamination level during food storage.

A non-homogeneous Markov early epidemic growth dynamics model. Application to the SARS-CoV-2 pandemic.

This work introduces a new markovian stochastic model that can be described as a non-homogeneous Pure Birth process. We propose a functional form of birth rate that depends on the number of individuals in the population and on the elapsed time, allowing us to model a contagion effect. Thus, we model the early stages of an epidemic. The number of individuals then becomes the infectious cases and the birth rate becomes the incidence rate. We obtain this way a process that depends on two competitive phenomena, infection and immunization. Variations in those rates allow us to monitor how effective the actions taken by government and health organizations are. From our model, three useful indicators for the epidemic evolution over time are obtained: the immunization rate, the infection/immunization ratio and the mean time between infections (MTBI). The proposed model allows either positive or negative concavities for the mean value curve, provided the infection/immunization ratio is either greater or less than one. We apply this model to the present SARS-CoV-2 pandemic still in its early growth stage in Latin American countries. As it is shown, the model accomplishes a good fit for the real number of both positive cases and deaths. We analyze the evolution of the three indicators for several countries and perform a comparative study between them. Important conclusions are obtained from this analysis.

Comparing birth experience and birth outcome of vaginal births between induced and spontaneous onset of labour: a prospective study.

PURPOSE: In developed countries, around 25% of all births involve labour induction. Studies have indicated that labour induction negatively influences the birth experience as well as the birth process. However, the impact of labour induction when only considering vaginal deliveries has not been studied yet, which was the purpose of the present study. METHODS: 186 women who gave birth vaginally took part in this prospective study. 95 women gave birth after spontaneous onset of labour (SL-group) and 91 women received a labour induction (LI-group). Eight to 72 h after birth, the women filled in the revised version of the standardised Childbirth Experience Questionnaire, which examines the birth experience in four dimensions (Own Capacity, Perceived Safety, Participation and Professional Support). Medical details regarding birth and fetal outcomes were taken from the medical records. RESULTS: Birth outcomes (the number of epidural anaesthesia, the duration of birth, birth risks and childbirth injuries) as well as fetal outcomes (APGAR after 1 and 5 min and arterial cord pH) did not differ between the groups. Regarding the subjective birth experience, the LI-group indicated significantly lower values for Perceived Safety and Participation compared to the SL-group, while there were no differences for the dimensions Own Capacity and Professional Support. DISCUSSION: Successful labour induction resulting in a vaginal birth did not negatively influence birth and fetal outcomes and only partly affected the women's birth experience. The negative impact of labour induction on the dimensions Perceived Safety and Participation should sensitize midwives in order to provide optimal support.

Corrective effects of maternal extreme flexure and hip abduction combined with contralateral side-lying on persistent foetal occipito-posterior position.

AIMS: To observe the corrective effects of maternal extreme flexure and hip abduction combined with contralateral side-lying on persistent foetal occipito-posterior position. BACKGROUND: Digital rotation and other methods are used for correction of a persistent foetal occipito-posterior position. However, digital rotation readily causes damage to mother and foetus, and the correction rates of other methods are low. DESIGN: In this observational study, pregnant women were randomly divided into 2 groups according to different postures and their outcomes were compared. METHODS: A total of 238 women with persistent foetal occipito-posterior position gave birth in our hospital between January 2015 and June 2017. Of these 238 cases, 12 women declined to participate. The 226 pregnant women were divided into study group (maternal extreme flexure and hip abduction combined with contralateral side-lying, n = 114) and control group (contralateral side-lying alone, n = 112). RESULTS: The correction and spontaneous labour rates were higher in the study group than in the control group (P < .05). The duration between initial and successful correction and birth process were shorter in the study group than in the control group (P < .05). CONCLUSION: Maternal extreme flexure and hip abduction combined with contralateral side-lying has better correction effect on persistent foetal occipito-posterior position.

Caesarean section rate reduced by a redesigned birthing room. Results of a quality improvement intervention at a hospital in Democratic Republic of Congo.

OBJECTIVE: To evaluate the influence of a new birthing room at a tertiary hospital in eastern Democratic Republic of Congo (DRC), on the caesarean section (CS) rate in women classified as Robson group 1, i.e., nulliparous women at term with spontaneous onset of labour of one foetus in cephalic presentation. METHOD: As part of quality improvement interventions, a new birthing room designed to promote person-centredness was constructed at the labour ward at Panzi General Referral Hospital in DRC. In a quasi-experimental study on women classified as Robson 1, a comparison was performed between the group being cared for in the new birthing room and the group being cared for in the general birthing room. The main outcome measure was CS rate. RESULTS: In the new person-centred birthing room, the CS rate was 17.1 % versus 28.4 % in women cared for in the general birthing room (p-value 0.001). There was also a higher presence of accompanying persons (p-value < 0.0001) and less use of synthetic oxytocin for the augmentation of labour (p-value 0.024). No difference in fear and childbirth experience was identified between women in the two rooms. CONCLUSION: The results demonstrate that it is possible, in a low-income country as the Democratic Republic of Congo, to reduce the CS rate in women classified as Robson 1 by adapting the birthing environment to be more person-centred, without compromising other obstetric and neonatal outcomes.

Promoting the participation of low-risk pregnant women in the child birth process by developing a birth plan: The protocol of an action research study.

BACKGROUND: The birth plan reflects the preferences and expectations of women in the delivery process and can be designed with the participation of women and her partner and implement as a basis for midwifery care during childbirth. This research was designed to promote the participation of low-risk pregnant women in the child birth process by developing a birth plan. MATERIALS AND METHODS: The present study is a participatory action research designed in a single specialized, main maternity hospital in Isfahan, Iran. This study was conducted in four stages proposed by the Kemmis, including planning, action, observation, and reflection with the participation of all midwives, gynecologists, and managers who involved in childbirth. CONCLUSIONS: Considering the importance of childbirth as an opportunity for participation and empowerment of women, it seems that designing a birth plan based on the preferences of these women and all people involved in this process can strengthen women's participation in child birth process.

Modelling the reproductive power function.

This paper discusses methods of estimating the reproductive power and the accompanying survival function of communicable events, e.g. infectious disease transmission. The early stage of an outbreak can be described by the infectiousness of the outbreak process, but in later stages of the outbreak, this is complicated by factors such as changing contact patterns and the impact of control measures. It is important to take these factors into account in order to get a good, if approximate, model for an outbreak process. This paper proposes a non-homogeneous birth process and regression model for the reproductive power function, similar to models in discrete survival analysis. A baseline reproductive power function gives a description of the outbreak when covariates are at their baseline values. As an illustration these methods are applied to an avian influenza (H5N1) outbreak among poultry in Thailand.

Effect of an educational program based on cognitive behavioral techniques on fear of childbirth and the birth process.

Objective: This study determined the effect of an educational program based on cognitive behavioral techniques (CBT) provided for pregnant women to address their fear of childbirth. Methods: This study was conducted experimentally using pretest-posttest and a control group. A total of 111 Turkish pregnant women were recruited with 52 in the intervention group and 59 in the control group. The intervention group attended the educational program on coping with childbirth fears based on CBT, which took 3 weeks over six sessions. The Wijma Delivery Expectancy/Experience Questionnaire, version-A (W-DEQ-A) was administered to both groups as the posttest. The researchers monitored the pregnant women's labor and delivery and the State Anxiety Inventory (SAI), Numeric Pain Rating Scale (NPRS) and Birth Process Evaluation Form were completed. Results: The post-education W-DEQ-A score was 63.5 in the control group and 39.4 in the intervention group (p < .001). Their labor pain was lower, the second stage of labor was shorter and birth was more satisfactory for the intervention group than for the control group (p < .05). The CBT-based educational program and pain severity during childbirth were the significant predictors of satisfaction with childbirth (ß = 0.354; ß = -0.324, respectively; p < .05 for all). Conclusions: The CBT-based educational program on coping with childbirth fears reduced pregnant women's fear of childbirth and positively affected their birth experience.

Needs of fathers during labour and childbirth: A cross-sectional study.

Fathers play an important role in the childbearing process, but are sometimes sidelined by midwives. The objectives were: identify fathers' needs during the labor and childbirth process; determine if their needs were met by midwives; and identify variables influencing these needs. The questionnaire was designed based on a systematic literature search and validated by a multistage consensus method. Data were collected during a cross-sectional study in two maternity wards in Belgium, where a medical-led model is used. Fathers present during natural childbirth were recruited via consecutive sampling. Based on multivariate analyses, fathers with a higher education level and multiparous fathers needed less information about the process of birth compared to less educated fathers (p<0.05; OR=4.08; 95% CI=1.02-16.31) or first-time fathers (p<0.001; OR=0.04; 95% CI=0.01-0.18). For multiparous fathers, a tour of the delivery room was less important than for primiparous fathers (p=0.005; OR=0.14; 95% CI=0.03-0.54). Married fathers needed less information on how to support their partners physically (p<0.005; OR=0.18; 95% CI=0.06-0.59) and emotionally (p=0.01; OR=0.24; 95% CI=0.08-0.72) compared to cohabiting fathers. Information needs are more important to fathers compared to needs focusing on the birth experience or their involvement. Socio-demographic variables like educational level, parity, and marital status were associated with fathers' needs. Midwives need to be aware of fathers' needs during the birth process and to fulfill these needs appropriately.

Possible relationship between general and pregnancy-related anxiety during the first half of pregnancy and the birth process: a prospective cohort study.

OBJECTIVES: The rate of interventions during childbirth has increased dramatically during the last decades. Maternal anxiety might play a role in the progress of the labour process and interventions during labour. This study aimed to identify associations between anxiety in the first half of pregnancy and the birth process, including any interventions required during labour. In addition, differences in the associations by parity and ethnicity were explored. DESIGN: Prospective cohort study. SETTING: Primary care midwifery practices and secondary/tertiary care obstetric practices in Amsterdam, participating in the multiethnic ABCD (Amsterdam Born Children and their Development) study (participation rate 96%; response 8266/12 373 (67%)). PARTICIPANTS: Included were women with singletons, alive at labour start, with a gestational age ≥24 weeks (n=6443). INDEPENDENT VARIABLE: General anxiety (State-Trait Anxiety Inventory state) and pregnancy-related anxiety (Pregnancy-Related Anxieties Questionnaire (PRAQ)) were self-reported in the first half of pregnancy. OUTCOMES: Associations between both forms of anxiety and several indicators of the birth process were analysed. Subgroup analyses were performed for parity and ethnicity. RESULTS: The prevalence of high general anxiety (State-Trait Anxiety Inventory score ≥43) and pregnancy-related anxiety (PRAQ score ≥P90) were 30.9% and 11.0%, respectively. After adjustment, in nulliparae, both general anxiety and pregnancy-related anxiety were associated with pain relief and/or sedation (OR for general anxiety 1.23; 95% CI 1.02 to 1.48; OR for pregnancy-related anxiety 1.45; 95% CI 1.14 to 1.85). In multiparae, general anxiety was associated with induction of labour (OR 1.53; 95% CI 1.16 to 2.03) and pregnancy-related anxiety was associated with primary caesarean section (OR 1.66; 95% CI 1.02 to 2.70). Associations were largely similar for all ethnicities. CONCLUSIONS: High levels of general and pregnancy-related anxiety in early pregnancy contribute modestly to more interventions during the birth process with similar associations between ethnic groups, but with some differences between nulliparae and multiparae.

Intrapartum practices to limit vertical transmission of HIV.

The need to improve health services to HIV-positive women requires a specific focus on limiting mother-to-child transmission. Vertical transmission most often takes place during the intrapartum period; hence, it is essential to alert midwives to what constitutes safe or risky intrapartum practices. Midwives in the southern region of the North West Province of South Africa were surveyed for their knowledge of safe intrapartum practices that can limit vertical transmission of HIV, consequently indicating which intrapartum practices prevail in the region. We used a quantitative survey design and collected data by means of a questionnaire and checklist. A purposeful availability sample of 31 midwives who work in all four hospitals in the province was used and a random sample of 401 obstetric records was audited. Data were analysed by means of frequency analysis, effect sizes and cross-reference. A slight majority of the midwives had sufficient knowledge to distinguish between risky and safe practices. However, safe intrapartum practices are not always carried out and this raises concerns. Accordingly, we formulate general recommendations for nursing education, future research, and midwifery practice. In particular we suggest ways the national Guidelines for Maternity Care in South Africa may be adapted and better implemented to enhance safe intrapartum practices to limit vertical transmission of HIV.

Experiências e expressões de gestantes na interação com o sistema de saúde: um enfoque fotoetnográfico / Pregnant women's experiences and expressions related to the interaction with the health system: a pictorial ethnographic approach

Este trabalho de cunho etnográfico teve por objetivo compreender a experiência da mulher, no seu contato com o sistema de saúde, por ocasião do parto. Para tanto, adotou-se como referencial teórico a Antropologia Cultural. A coleta de dados foi realizada por meio da observação participante, do recurso fotográfico e da entrevista. As fotografias foram realizadas pelas próprias gestantes - colaboradoras do estudo, cujo pré-natal era realizado nas Unidades Básicas de Saúde da área de abrangência do hospital-escola, cenário cultural desta investigação. Os dados foram apresentados na forma de narrativa e a sua análise se deu por meio do Método Biográfico Interpretativo. Foram extraídas oito categorias culturais, das quais emergiram três relevantes temas, nos quais as colaboradoras, a princípio, resgatam e classificam, por meio da sua memória autobiográfica, as suas experiências e as suas histórias de vida, na condição de ratificar os resultados dos eventos significativos considerados positivos ou de fazer uma releitura dos eventos tidos como negativos. A partir dessa concepção, prosseguem vislumbrando o processo de nascimento em todas as suas dimensões, utilizando, para o alcance dessa finalidade, o olhar fotográfico, que ora permitiu que fatos fossem registrados e absorvidos e ora evitou que suas lentes captassem aquilo que seria difícil elaborar naquele momento. Os achados deste estudo permitiram ter uma visão compreensiva do conhecimento cultural das colaboradoras com relação à sua interação com o sistema de saúde, bem como de suas expectativas no ciclo gravídico-puerperal.

This study based on ethnography has aimed to understand the women experience, related to her contact with the health system, while she was pregnant. The cultural anthropology was used as the theoretical reference. The data collection was done by participant observation, pictorial resource and interview. The pictures were taken by the pregnant women - collaborators of the study, who had their prenatal attendance at the Health Basic Units, located in the area covered by the school hospital, which was considered the scenery of this study. The data were presented by narrative and their analyses were done based on the Interpretative and Biographical Method. It was taken out eight cultural categories, from which emerged three relevant themes. Initially, the collaborators used their autobiographical memory to rescue and classify their experiences and life history trying to ratify the results of the important events considered positive, or even trying to reread the events they considered negative. From this conception on, they continued glimpsing the birth process in its entire dimension. To register and absorb the factors, the pregnant women used a camera to take pictures, which also helped them to avoid capturing those things that would be difficult for them to elaborate at that moment. The findings of this study allowed us to have a comprehensive vision of the collaborators' cultural knowledge related to their interaction with the health system, as well as their expectations of the puerperal gravid cycle.