Etiology and prognosis of pregnancy-related pelvic girdle pain; design of a longitudinal study

<p>Abstract</p> <p>Background</p> <p>Absence of knowledge of pregnancy-related pelvic girdle pain (PPGP) has prompted the start of a large cohort study in the Netherlands. The objective of this study was to investigate the prevalence and incidence of PPGP, to identify risk factors involved in the onset and to determine the prognosis of pregnancy-related pelvic girdle pain.</p> <p>Methods/design</p> <p>7,526 pregnant women of the southeast of the Netherlands participated in a prospective cohort study. During a 2-year period, they were recruited by midwives and gynecologists at 14 weeks of pregnancy. Participants completed a questionnaire at baseline, at 30 weeks of pregnancy, at 2 weeks after delivery, at 6 months after delivery and at 1 year after delivery. The study uses extensive questionnaires with questions ranging from physical complaints, limitations in activities, restriction in participation, work situation, demographics, lifestyle, pregnancy-related factors and psychosocial factors.</p> <p>Discussion</p> <p>This large-scale prospective cohort study will provide reliable insights in incidence, prevalence and factors related to etiology and prognosis of pregnancy-related pelvic girdle pain.</p

Biological control as an invasion process: disturbance and propagule pressure affect the invasion success of Lythrum salicaria biological control agents

Understanding the mechanisms behind the successful colonization and establishment of introduced species is important for both preventing the invasion of unwanted species and improving release programs for biological control agents. However, it is often not possible to determine important introduction details, such as date, number of organisms, and introduction location when examining factors affecting invasion success. Here we use biological control introduction data to assess the role of propagule pressure, disturbance, and residence time on invasion success of four herbivorous insect species introduced for the control of the invasive wetland plant, Lythrum salicaria, in the Columbia River Estuary. Two sets of field surveys determined persistence at prior release sites, colonization of new sites, and abundance within colonized sites. We quantified propagule pressure in four ways to examine the effect of different measurements. These included three measurements of introduction size (proximity to introduction site, introduction size at a local scale, and introduction size at a regional scale) and one measure of introduction number (number of introduction events in a region). Disturbance was examined along a tidal inundation gradient (distance from river mouth) and as habitat (island or mainland). Statistical models and model averaging were used to determine which factors were driving invasion success. In this study we found: (1) sparse evidence for the positive influence of propagule pressure on invasion success; (2) disturbance can negatively affect the invasion success of herbivorous insects; (3) the effects of disturbance and propagule pressure are species specific and vary among invasion stages, and (4) not all measures of propagule pressure show the same results, therefore single measures and proxies should be used cautiously