animals used (i.e., species/strain, sex, and age/weight). Most of the papers surveyed did not report using randomisation (87%) or blinding (86%) to reduce bias in animal selection and outcome assessment. Only 70% of the publications that used statistical methods fully described them and presented the results with a measure of precision or variability [5]. These findings are a cause for concern and are consistent with reviews of many research areas, including clinical studies, published in recent years [2–22].

https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.1000412&type=printable

Improving Bioscience Research Reporting: The ARRIVE Guidelines for Reporting Animal Research

A study with low statistical power has a reduced chance of detecting a true effect, but it is less well appreciated that low power also reduces the likelihood that a statistically significant result reflects a true effect. Here, we show that the average statistical power of studies in the neurosciences is very low. The consequences of this include overestimates of effect size and low reproducibility of results. There are also ethical dimensions to this problem, as unreliable research is inefficient and wasteful. Improving reproducibility in neuroscience is a key priority and requires attention to well-established but often ignored methodological principles.

/pdf/power-failure-why-small-sample-size-undermines-the-4ftwwuexp7.pdf

Power failure: why small sample size undermines the reliability of neuroscience

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(07)61238-0.pdf

No health without mental health.

Depression is related to the normal emotions of sadness and bereavement, but it does not remit when the external cause of these emotions dissipates, and it is disproportionate to their cause. Classic severe states of depression often have no external precipitating cause. It is difficult, however, to draw clear distinctions between depressions with and those without psychosocial precipitating events. 1 The diagnosis of major depressive disorder requires a distinct change of mood, characterized by sadness or irritability and accompanied by at least several psychophysiological changes, such as disturbances in sleep, appetite, or sexual desire; constipation; loss of the ability to experience pleasure in work or with friends; crying; suicidal thoughts; and slowing of speech and action. These changes must last a minimum of 2 weeks and interfere considerably with work and family relations. On the basis of this broad definition, the lifetime incidence of depression in the United States is more than 12% in men and 20% in women. 2 Some have advocated a much narrower definition of severe depression, which they call melancholia or vital depression. 3 A small percentage of patients with major depression have had or will have manic episodes consisting of hyperactivity, euphoria, and an increase in pleasure seeking. Although some pathogenetic mechanisms in these cases and in cases of major depressive disorder overlap, a history of mania defines a distinct illness termed bipolar disorder. 4 Depression is a heterogeneous disorder with a highly variable course, an inconsistent response to treatment, and no established mechanism. This review presents the major current approaches to understanding the biologic mechanisms of major depression.

/pdf/major-depressive-disorder-rkewp1bncd.pdf

Major depressive disorder.

Systematic Reviews (SRs) of experimental animal studies are not yet common practice, but awareness of the merits of conducting such SRs is steadily increasing. As animal intervention studies differ from randomized clinical trials (RCT) in many aspects, the methodology for SRs of clinical trials needs to be adapted and optimized for animal intervention studies. The Cochrane Collaboration developed a Risk of Bias (RoB) tool to establish consistency and avoid discrepancies in assessing the methodological quality of RCTs. A similar initiative is warranted in the field of animal experimentation. We provide an RoB tool for animal intervention studies (SYRCLE’s RoB tool). This tool is based on the Cochrane RoB tool and has been adjusted for aspects of bias that play a specific role in animal intervention studies. To enhance transparency and applicability, we formulated signalling questions to facilitate judgment. The resulting RoB tool for animal studies contains 10 entries. These entries are related to selection bias, performance bias, detection bias, attrition bias, reporting bias and other biases. Half these items are in agreement with the items in the Cochrane RoB tool. Most of the variations between the two tools are due to differences in design between RCTs and animal studies. Shortcomings in, or unfamiliarity with, specific aspects of experimental design of animal studies compared to clinical studies also play a role. SYRCLE’s RoB tool is an adapted version of the Cochrane RoB tool. Widespread adoption and implementation of this tool will facilitate and improve critical appraisal of evidence from animal studies. This may subsequently enhance the efficiency of translating animal research into clinical practice and increase awareness of the necessity of improving the methodological quality of animal studies.

/pdf/syrcle-s-risk-of-bias-tool-for-animal-studies-4t6robf3lr.pdf

SYRCLE’s risk of bias tool for animal studies

Background
Episiotomy is done to prevent severe perineal tears, but its routine use has been questioned. The relative effects of midline compared with midlateral episiotomy are unclear.

Objectives
The objective of this review was to assess the effects of restrictive use of episiotomy compared with routine episiotomy during vaginal birth.

Search methods
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2008).

Selection criteria
Randomized trials comparing restrictive use of episiotomy with routine use of episiotomy; restrictive use of mediolateral episiotomy versus routine mediolateral episiotomy; restrictive use of midline episiotomy versus routine midline episiotomy; and use of midline episiotomy versus mediolateral episiotomy.

Data collection and analysis
The two review authors independently assessed trial quality and extracted the data.

Main results
We included eight studies (5541 women). In the routine episiotomy group, 75.15% (2035/2708) of women had episiotomies, while the rate in the restrictive episiotomy group was 28.40% (776/2733). Compared with routine use, restrictive episiotomy resulted in less severe perineal trauma (relative risk (RR) 0.67, 95% confidence interval (CI) 0.49 to 0.91), less suturing (RR 0.71, 95% CI 0.61 to 0.81) and fewer healing complications (RR 0.69, 95% CI 0.56 to 0.85). Restrictive episiotomy was associated with more anterior perineal trauma (RR 1.84, 95% CI 1.61 to 2.10). There was no difference in severe vaginal/perineal trauma (RR 0.92, 95% CI 0.72 to 1.18); dyspareunia (RR 1.02, 95% CI 0.90 to 1.16); urinary incontinence (RR 0.98, 95% CI 0.79 to 1.20) or several pain measures. Results for restrictive versus routine mediolateral versus midline episiotomy were similar to the overall comparison.

Authors' conclusions
Restrictive episiotomy policies appear to have a number of benefits compared to policies based on routine episiotomy. There is less posterior perineal trauma, less suturing and fewer complications, no difference for most pain measures and severe vaginal or perineal trauma, but there was an increased risk of anterior perineal trauma with restrictive episiotomy.

/pdf/episiotomy-for-vaginal-birth-4mxfdb9j0o.pdf

Episiotomy for vaginal birth

Objective To examine concordance between treatment effects in animal experiments and clinical trials.
 Study design
 Systematic review.
 Data sources
 Medline, Embase, SIGLE, NTIS, Science Citation Index, CAB, BIOSIS.
 Study selection
 Animal studies for interventions with unambiguous evidence of a treatment effect (benefit or harm) in clinical trials: head injury, antifibrinolytics in haemorrhage, thrombolysis in acute ischaemic stroke, tirilazad in acute ischaemic stroke, antenatal corticosteroids to prevent neonatal respiratory distress syndrome, and bisphosphonates to treat osteoporosis.
 Review methods
 Data were extracted on study design, allocation concealment, number of randomised animals, type of model, intervention, and outcome.
 Results
 Corticosteroids did not show any benefit in clinical trials of treatment for head injury but did show a benefit in animal models (pooled odds ratio for adverse functional outcome 0.58, 95% confidence interval 0.41 to 0.83). Antifibrinolytics reduced bleeding in clinical trials but the data were inconclusive in animal models. Thrombolysis improved outcome in patients with ischaemic stroke. In animal models, tissue plasminogen activator reduced infarct volume by 24% (95% confidence interval 20% to 28%) and improved neurobehavioural scores by 23% (17% to 29%). Tirilazad was associated with a worse outcome in patients with ischaemic stroke. In animal models, tirilazad reduced infarct volume by 29% (21% to 37%) and improved neurobehavioural scores by 48% (29% to 67%). Antenatal corticosteroids reduced respiratory distress and mortality in neonates whereas in animal models respiratory distress was reduced but the effect on mortality was inconclusive (odds ratio 4.2, 95% confidence interval 0.85 to 20.9). Bisphosphonates increased bone mineral density in patients with osteoporosis. In animal models the bisphosphonate alendronate increased bone mineral density compared with placebo by 11.0% (95% confidence interval 9.2% to 12.9%) in the combined results for the hip region. The corresponding treatment effect in the lumbar spine was 8.5% (5.8% to 11.2%) and in the combined results for the forearms (baboons only) was 1.7% (−1.4% to 4.7%). Conclusions
 Discordance between animal and human studies may be due to bias or to the failure of animal models to mimic clinical disease adequately.

https://www.bmj.com/content/bmj/334/7586/197.full.pdf

Comparison of treatment effects between animal experiments and clinical trials: systematic review

Objective To evaluate factors predisposing women to chronic and recurrent pelvic pain.

Design, data sources, and methods Systematic review of relevant studies without language restrictions identified through Medline, Embase, PsycINFO, Cochrane Library. SCISEARCH, conference papers, and bibliographies of retrieved primary and review articles. Two reviewers independently extracted data on study characteristics, quality, and results. Exposure to risk factors was compared between women with and without pelvic pain. Results were pooled within subgroups defined by type of pain and risk factors.

Results There were 122 studies (in 111 articles) of which 63 (in 64 286 women) evaluated 54 risk factors for dysmenorrhoea, 19 (in 18 601 women) evaluated 14 risk factors for dyspareunia, and 40 (in 12 040 women) evaluated 48 factors for non-cyclical pelvic pain. Age < 30 years, low body mass index, smoking, earlier menarche (< 12 years), longer cycles, heavy menstrual flow, nulliparity, premenstrual syndrome, sterilisation, clinically suspected pelvic inflammatory disease, sexual abuse, and psychological symptoms were associated with dysmenorrhoea. Younger age at first childbirth, exercise, and oral contraceptives were negatively associated with dysmenorrhoea. Menopause, pelvic inflammatory disease, sexual abuse, anxiety, and depression were associated with dyspareunia. Drug or alcohol abuse, miscarriage, heavy menstrual flow, pelvic inflammatory disease, previous caesarean section, pelvic pathology, abuse, and psychological comorbidity were associated with an increased risk of non-cyclical pelvic pain.

Conclusion Several gynaecological and psychosocial factors are strongly associated with chronic pelvic pain. Randomised controlled trials of interventions targeting these potentially modifiable factors are needed to assess their clinical relevance in chronic pelvic pain.

https://www.bmj.com/content/bmj/332/7544/749.full.pdf

Factors predisposing women to chronic pelvic pain: systematic review

https://thelancet.com/pdfs/journals/lancet/PIIS0140-6736(15)00045-8.pdf

Luciano Mignini

Papers

Episiotomy for vaginal birth

Comparison of treatment effects between animal experiments and clinical trials: systematic review

Factors predisposing women to chronic pelvic pain: systematic review

Epilepsy in pregnancy and reproductive outcomes: a systematic review and meta-analysis

Mapping the theories of preeclampsia: the role of homocysteine.