Methods of term labour induction for women with a previous caesarean section

Background: Women with a prior caesarean delivery have an increased risk of uterine rupture and for women subsequently requiring induction of labour it is unclear which method is preferable to avoid adverse outcomes. This is an update of a review that was published in 2013. Objectives: To assess the benefits and harms associated with different methods used to induce labour in women who have had a previous caesarean birth. Search methods: We searched Cochrane Pregnancy and Childbirth's Trials Register (31 August 2016) and reference lists of retrieved studies. Selection criteria: Randomised controlled trials (RCTs) comparing any method of third trimester cervical ripening or labour induction, with placebo/no treatment or other methods in women with prior caesarean section requiring labour induction in a subsequent pregnancy. Data collection and analysis: Two review authors independently assessed studies for inclusion and trial quality, extracted data, and checked them for accuracy. Main results: Eight studies (data from 707 women and babies) are included in this updated review. Meta-analysis was not possible because studies compared different methods of labour induction. All included studies had at least one design limitation (i.e. lack of blinding, sample attrition, other bias, or reporting bias). One study stopped prematurely due to safety concerns. Vaginal PGE2 versus intravenous oxytocin: (one trial, 42 women): no clear differences for caesarean section (risk ratio (RR) 0.67, 95% confidence interval (CI) 0.22 to 2.03, evidence graded low), serious neonatal morbidity or perinatal death (RR 3.00, 95% CI 0.13 to 69.70, evidence graded low), serious maternal morbidity or death (RR 3.00, 95% CI 0.13 to 69.70, evidence graded low). Also no clear differences between groups for the reported secondary outcomes. The GRADE outcomes vaginal delivery not achieved within 24 hours, and uterine hyperstimulation with fetal heart rate changes were not reported. Vaginal misoprostol versus intravenous oxytocin (one trial, 38 women): this trial stopped early because one woman who received misoprostol had a uterine rupture (RR 3.67, 95% CI 0.16 to 84.66) and one had uterine dehiscence. No other outcomes (including GRADE outcomes) were reported. Foley catheter versus intravenous oxytocin (one trial, subgroup of 53 women): no clear difference between groups for vaginal delivery not achieved within 24 hours (RR 1.47, 95% CI 0.89 to 2.44, evidence graded low), uterine hyperstimulation with fetal heart rate changes (RR 3.11, 95% CI 0.13 to 73.09, evidence graded low), and caesarean section (RR 0.93, 95% CI 0.45 to 1.92, evidence graded low). There were also no clear differences between groups for the reported secondary outcomes. The following GRADE outcomes were not reported: serious neonatal morbidity or perinatal death, and serious maternal morbidity or death. Double-balloon catheter versus vaginal PGE2 (one trial, subgroup of 26 women): no clear difference in caesarean section (RR 0.97, 95% CI 0.41 to 2.32, evidence graded very low). Vaginal delivery not achieved within 24 hours, uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death were not reported. Oral mifepristone versus Foley catheter (one trial, 107 women): no primary/GRADE outcomes were reported. Fewer women induced with mifepristone required oxytocin augmentation (RR 0.54, 95% CI 0.38 to 0.76). There were slightly fewer cases of uterine rupture among women who received mifepristone, however this was not a clear difference between groups (RR 0.29, 95% CI 0.08 to 1.02). No other secondary outcomes were reported. Vaginal isosorbide mononitrate (IMN) versus Foley catheter (one trial, 80 women): fewer women induced with IMN achieved a vaginal delivery within 24 hours (RR 2.62, 95% CI 1.32 to 5.21, evidence graded low). There was no difference between groups in the number of women who had a caesarean section (RR 1.00, 95% CI 0.39 to 2.59, evidence graded very low). More women induced with IMN required oxytocin augmentation (RR 1.65, 95% CI 1.17 to 2.32). There were no clear differences in the other reported secondary outcomes. The following GRADE outcomes were not reported: uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death. 80 mL versus 30 mL Foley catheter (one trial, 154 women): no clear difference between groups for the primary outcomes: vaginal delivery not achieved within 24 hours (RR 1.05, 95% CI 0.91 to 1.20, evidence graded moderate) and caesarean section (RR 1.05, 95% CI 0.89 to 1.24, evidence graded moderate). However, more women induced using a 30 mL Foley catheter required oxytocin augmentation (RR 0.81, 95% CI 0.66 to 0.98). There were no clear differences between groups for other secondary outcomes reported. Several GRADE outcomes were not reported: uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death. Vaginal PGE2 pessary versus vaginal PGE2 tablet (one trial, 200 women): no difference between groups for caesarean section (RR 1.09, 95% CI 0.74 to 1.60, evidence graded very low), or any of the reported secondary outcomes. Several GRADE outcomes were not reported: vaginal delivery not achieved within 24 hours, uterine hyperstimulation with fetal heart rate changes, serious neonatal morbidity or perinatal death, and serious maternal morbidity or death.RCT evidence on methods of induction of labour for women with a prior caesarean section is inadequate, and studies are underpowered to detect clinically relevant differences for many outcomes. Several studies reported few of our prespecified outcomes and reporting of infant outcomes was especially scarce. The GRADE level for quality of evidence was moderate to very low, due to imprecision and study design limitations.High-quality, adequately-powered RCTs would be the best approach to determine the optimal method for induction of labour in women with a prior caesarean birth. However, such trials are unlikely to be undertaken due to the very large numbers needed to investigate the risk of infrequent but serious adverse outcomes (e.g. uterine rupture). Observational studies (cohort studies), including different methods of cervical ripening, may be the best alternative. Studies could compare methods believed to provide effective induction of labour with low risk of serious harm, and report the outcomes listed in this review.Helen M West, Marta Jozwiak, Jodie M Dod

Planned early delivery versus expectant management for hypertensive disorders from 34 weeks gestation to term

Cluver, C., et al. 2017. Planned early delivery versus expectant management for hypertensive disorders from 34 weeks gestation to term. Cochrane Database of Systematic Reviews, 1:1-76, Art. CD009273, doi:10.1002/14651858.CD009273.pub2The original publication is available at https://www.cochranelibrary.comBackground: Hypertensive disorders in pregnancy are significant contributors to maternal and perinatal morbidity and mortality. These disorders include well‐controlled chronic hypertension, gestational hypertension (pregnancy‐induced hypertension) and mild pre‐eclampsia. The definitive treatment for these disorders is planned early delivery and the alternative is to manage the pregnancy expectantly if severe uncontrolled hypertension is not present, with close maternal and fetal monitoring. There are benefits and risks associated with both, so it is important to establish the safest option. Objectives: To assess the benefits and risks of a policy of planned early delivery versus a policy of expectant management in pregnant women with hypertensive disorders, at or near term (from 34 weeks onwards). Search methods: We searched Cochrane Pregnancy and Childbirth Trials Register (12 January 2016) and reference lists of retrieved studies. Selection criteria: Randomised trials of a policy of planned early delivery (by induction of labour or by caesarean section) compared with a policy of delayed delivery ("expectant management") for women with hypertensive disorders from 34 weeks' gestation. Cluster‐randomised trials would have been eligible for inclusion in this review, but we found none. Studies using a quasi‐randomised design are not eligible for inclusion in this review. Similarly, studies using a cross‐over design are not eligible for inclusion, because they are not a suitable study design for investigating hypertensive disorders in pregnancy. Data collection and analysis: Two review authors independently assessed eligibility and risks of bias. Two review authors independently extracted data. Data were checked for accuracy. Main results: We included five studies (involving 1819 women) in this review. There was a lower risk of composite maternal mortality and severe morbidity for women randomised to receive planned early delivery (risk ratio (RR) 0.69, 95% confidence interval (CI) 0.57 to 0.83, two studies, 1459 women (evidence graded high)). There were no clear differences between subgroups based on our subgroup analysis by gestational age, gestational week or condition. Planned early delivery was associated with lower risk of HELLP syndrome (RR 0.40, 95% CI 0.17 to 0.93, 1628 women; three studies) and severe renal impairment (RR 0.36, 95% CI 0.14 to 0.92, 100 women, one study). There was not enough information to draw any conclusions about the effects on composite infant mortality and severe morbidity. We observed a high level of heterogeneity between the two studies in this analysis (two studies, 1459 infants, I2 = 87%, Tau2 = 0.98), so we did not pool data in meta‐analysis. There were no clear differences between subgroups based on our subgroup analysis by gestational age, gestational week or condition. Planned early delivery was associated with higher levels of respiratory distress syndrome (RR 2.24, 95% CI 1.20 to 4.18, three studies, 1511 infants), and NICU admission (RR 1.65, 95% CI 1.13 to 2.40, four studies, 1585 infants). There was no clear difference between groups for caesarean section (RR 0.91, 95% CI 0.78 to 1.07, 1728 women, four studies, evidence graded moderate), or in the duration of hospital stay for the mother after delivery of the baby (mean difference (MD) ‐0.16 days, 95% CI ‐0.46 to 0.15, two studies, 925 women, evidence graded moderate) or for the baby (MD ‐0.20 days, 95% CI ‐0.57 to 0.17, one study, 756 infants, evidence graded moderate). Two fairly large, well‐designed trials with overall low risk of bias contributed the majority of the evidence. Other studies were at low or unclear risk of bias. No studies attempted to blind participants or clinicians to group allocation, potentially introducing bias as women and staff would have been aware of the intervention and this may have affected aspects of care and decision‐making. The level of evidence was graded high (composite maternal mortality and morbidity), moderate (caesarean section, duration of hospital stay after delivery for mother, and duration of hospital stay after delivery for baby) or low (composite infant mortality and morbidity). Where the evidence was downgraded, it was mostly because the confidence intervals were wide, crossing both the line of no effect and appreciable benefit or harm. Authors' conclusions: For women suffering from hypertensive disorders of pregnancy after 34 weeks, planned early delivery is associated with less composite maternal morbidity and mortality. There is no clear difference in the composite outcome of infant mortality and severe morbidity; however, this is based on limited data (from two trials) assessing all hypertensive disorders as one group. Further studies are needed to look at the different types of hypertensive diseases and the optimal timing of delivery for these conditions. These studies should also include infant and maternal morbidity and mortality outcomes, caesarean section, duration of hospital stay after delivery for mother and duration of hospital stay after delivery for baby. An individual patient meta‐analysis on the data currently available would provide further information on the outcomes of the different types of hypertensive disease encountered in pregnancy.https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD009273.pub2/fullPublisher's versio

Phosphorus recovery as struvite: recent concerns for use of seed, alternative Mg source, nitrogen conservation and fertilizer potential

Finite availability of phosphorus (P) resources makes recovery of this non-substitutable plant nutrient from alternative waste sources an increasingly attractive option of renewed interest. In this context, feasibility of struvite (MgNH4PO4·6H2O) recovery, an alternative P fertilizer is already demonstrated at laboratory scale from range of waste streams of farm, municipal and industrial origin, with reasonably high orthophosphate recovery efficiency (∼90%). However, apart from a few commercial extraction units using municipal sludge and urine, large scale struvite recovery is not widely adopted for many of these sources. Moreover, need of some research interventions that are restricting its profitable recovery are also highlighted by earlier studies. To increase recovery efficiency from identified potential sources in terms of cost and energy input, research focuses on some new aspects of the process such as prospects of alternative recyclable magnesium sources, different seed materials and their related issues, which are analyzed in this review. Prospects of nitrogen conservation through struvite recovery and fertilizer value of struvite considering its properties, comparative performance with conventional fertilizer and interaction with soil and plant growth are also critically reviewed

The response of soil microbial diversity and abundance to long-term application of biosolids

The disposal of biosolids poses a major environmental and economic problem. Agricultural use is generally regarded as the best means of disposal. However, its impact on soil ecosystems remains uncertain. Biosolids can improve soil properties by supplying nutrients and increasing organic matter content but there is also a potentially detrimental effect arising from the introduction of heavy metals into soils. To assess the balance between these competing effects on soil health, we investigated soil bacterial and fungal diversity and community structure at a site that has been dedicated to the disposal of sewage sludge for over 100 years. Terminal restriction fragment length polymorphism (T-RFLP) was used to characterize the soil microbial communities. The most important contaminants at the site were Ni, Cu, Zn, Cd, and Pb. Concentrations were highly correlated and Zn concentration was adopted as a good indicator of the overall (historical) biosolids loading. A biosolids loading, equivalent to 700–1000 mg kg−1 Zn appeared to be optimal for maximum bacterial and fungal diversity. This markedly exceeds the maximum soil Zn concentration of 300 mg kg−1permitted under the current UK Sludge (use in agriculture) Regulations. Redundancy analysis (RDA) suggested that the soil microbial communities had been altered in response to the accumulation of trace metals, especially Zn, Cd, and Cu. We believe this is the first time the trade-off between positive and negative effects of long term (>100 years) biosolids disposal on soil microorganisms have been observed in the field situation

The Fe and Zn isotope composition of deep mantle source regions: Insights from Baffin Island picrites

Young (61 Ma) unaltered picrites from Baffin Island, northwest Canada, possess some of the highest 3He/4He (up to 50 Ra) seen on Earth, and provide a unique opportunity to study primordial mantle that has escaped subsequent chemical modification. These high-degree partial melts also record anomalously high 182W/184W ratios, but their Sr-Nd-Hf-Pb isotopic compositons (including 142Nd) are indistinguishable from those of North Atlantic mid-ocean ridge basalts. New high precision Fe and Zn stable isotope analyses of Baffin Island picrites show limited variability with δ56Fe ranging from −0.03‰ to 0.13‰ and δ66Zn varying from 0.18‰ to 0.28‰. However, a clear inflection is seen in both sets of isotope data around the composition of the parental melt (MgO = 21 wt %; δ56Fe = 0.08 ± 0.04‰; and δ66Zn = 0.24 ± 0.03‰), with two diverging trends interpreted to reflect the crystallisation of olivine and spinel in low-MgO samples and the accumulation of olivine at higher MgO. Olivine mineral separates are significantly isotopically lighter than their corresponding whole rocks (δ56Fe ≥ −0.62‰ and δ66Zn ≥ −0.22‰), with analyses of individual olivine phenocrysts having extremely variable Fe isotope compositions (δ56Fe = −0.01‰ to −0.80‰). By carrying out modelling in three-isotope space, we show that the very negative Fe isotope compositions of olivine phenocryst are the result of kinetic isotope fractionation from disequilibrium diffusional processes. An excellent correlation is observed between δ56Fe and δ66Zn, demonstrating that Zn isotopes are fractionated by the same processes as Fe in simple systems dominated by magmatic olivine. The incompatible behaviour of Cu during magmatic evolution is consistent with the sulfide-undersaturated nature of these melts. Consequently Zn behaves as a purely lithophile element, and estimates of the bulk Earth Zn isotope composition based on Baffin Island should therefore be robust. The ancient undegassed lower mantle sampled at Baffin Island possesses a δ56Fe value that is within error of previous estimates of bulk mantle δ56Fe, however, our estimate of the Baffin mantle δ66Zn (0.20 ± 0.03‰) is significantly lower than some previous estimates. Comparison of our new data with those for Archean and Proterozoic komatiites is consistent with the Fe and Zn isotope composition of the mantle remaining constant from at least 3 Ga to the present day. By focusing on large-degree partial melts (e.g. komatiites and picrites) we are potenitally biasing our record to samples that will inevitably have interacted with, entrained and melted the ambient shallow mantle during ascent. For a major element such as Fe, that will continuosly participate in melting as it rises through the mantle, the final isotopic compositon of the magama will be a weighted average of the complete melting column. Thus it is unsuprising that minimal Fe isotope variation are seen between localities. In contrast, the unique geochemical signatures (e.g. He and W) displayed by the Baffin Island picrites are inferred to solely originate from the lowermost mantle and will be continuously diluted upon magma ascent

Biochar-mediated reductions in greenhouse gas emissions from soil amended with anaerobic digestates

This investigation examines nitrous oxide (N2O) fluxes from soil with simultaneous amendments of anaerobic digestates and biochar. The main source of anthropogenic emissions of N2O is agriculture and in particular, manure and slurry application to fields. Anaerobic digestates are increasingly used as a fertiliser and interest is growing in their potential as sources of N2O via nitrification and denitrification. Biochar is a stable product of pyrolysis and may affect soil properties such as cation exchange capacity and water holding capacity. Whilst work has been conducted on the effects of biochar amendment on N2O emissions in soils fertilised with mineral fertilisers and raw animal manures, little work to date has focused on the effects of biochar on nitrogen transformations within soil amended with anaerobic digestates. The aim of the current investigation was to quantify the effects of biochar application on ammonification, nitrification and N2O fluxes within soil amended with three anaerobic digestates derived from different feedstocks. A factorial experiment was undertaken in which a sandy loam soil (Dunnington Heath series) was either left untreated, or amended with three different anaerobic digestates and one of three biochar treatments; 0%, 1% or 3%. Nitrous oxide emissions were greatest from soil amended with anaerobic digestate originating from a maize feedstock. Biochar amendment reduced N2O emissions from all treatments, with the greatest effect observed in treatments with maximum emissions. The degree of N2O production and efficacy of biochar amelioration of gas emissions is discussed in context of soil microbial biomass and soil available carbon

Golgi duplication in Trypanosoma brucei

Duplication of the single Golgi apparatus in the protozoan parasite Trypanosoma brucei has been followed by tagging a putative Golgi enzyme and a matrix protein with variants of GFP. Video microscopy shows that the new Golgi appears de novo, near to the old Golgi, about two hours into the cell cycle and grows over a two-hour period until it is the same size as the old Golgi. Duplication of the endoplasmic reticulum (ER) export site follows exactly the same time course. Photobleaching experiments show that the new Golgi is not the exclusive product of the new ER export site. Rather, it is supplied, at least in part, by material directly from the old Golgi. Pharmacological experiments show that the site of the new Golgi and ER export is determined by the location of the new basal body

Extensive crustal extraction in Earth’s early history inferred from molybdenum isotopes

Estimates of the volume of the earliest crust based on zircon ages and radiogenic isotopes remain equivocal. Stable isotope systems, such as molybdenum, have the potential to provide further constraints but remain underused due to the lack of complementarity between mantle and crustal reservoirs. Here we present molybdenum isotope data for Archaean komatiites and Phanerozoic komatiites and picrites and demonstrate that their mantle sources all possess subchondritic signatures complementary to the superchondritic continental crust. These results confirm that the present-day degree of mantle depletion was achieved by 3.5 billion years ago and that Earth has been in a steady state with respect to molybdenum recycling. Mass balance modelling shows that this early mantle depletion requires the extraction of a far greater volume of mafic-dominated protocrust than previously thought, more than twice the volume of the continental crust today, implying rapid crustal growth and destruction in the first billion years of Earth’s history