Publications by authors named "Sarah J Davidson"

5 Publications

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Probiotics for preventing gestational diabetes.

Cochrane Database Syst Rev 2021 Apr 19;4:CD009951. Epub 2021 Apr 19.

School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia.

Background: Gestational diabetes mellitus (GDM) is associated with a range of adverse pregnancy outcomes for mother and infant. The prevention of GDM using lifestyle interventions has proven difficult. The gut microbiome (the composite of bacteria present in the intestines) influences host inflammatory pathways, glucose and lipid metabolism and, in other settings, alteration of the gut microbiome has been shown to impact on these host responses. Probiotics are one way of altering the gut microbiome but little is known about their use in influencing the metabolic environment of pregnancy. This is an update of a review last published in 2014.

Objectives: To systematically assess the effects of probiotic supplements used either alone or in combination with pharmacological and non-pharmacological interventions on the prevention of GDM.

Search Methods: We searched Cochrane Pregnancy and Childbirth's Trials Register,, the WHO International Clinical Trials Registry Platform (ICTRP) (20 March 2020), and reference lists of retrieved studies.

Selection Criteria: Randomised and cluster-randomised trials comparing the use of probiotic supplementation with either placebo or diet for the prevention of the development of GDM. Cluster-randomised trials were eligible for inclusion but none were identified. Quasi-randomised and cross-over design studies were not eligible for inclusion in this review. Studies presented only as abstracts with no subsequent full report of study results were only included if study authors confirmed that data in the abstract came from the final analysis. Otherwise, the abstract was left awaiting classification.

Data Collection And Analysis: Two review authors independently assessed study eligibility, extracted data and assessed risk of bias of included studies. Data were checked for accuracy.

Main Results: In this update, we included seven trials with 1647 participants. Two studies were in overweight and obese women, two in obese women and three did not exclude women based on their weight. All included studies compared probiotics with placebo. The included studies were at low risk of bias overall except for one study that had an unclear risk of bias. We excluded two studies, eight studies were ongoing and three studies are awaiting classification. Six included studies with 1440 participants evaluated the risk of GDM. It is uncertain if probiotics have any effect on the risk of GDM compared to placebo (mean risk ratio (RR) 0.80, 95% confidence interval (CI) 0.54 to 1.20; 6 studies, 1440 women; low-certainty evidence). The evidence was low certainty due to substantial heterogeneity and wide CIs that included both appreciable benefit and appreciable harm. Probiotics increase the risk of pre-eclampsia compared to placebo (RR 1.85, 95% CI 1.04 to 3.29; 4 studies, 955 women; high-certainty evidence) and may increase the risk of hypertensive disorders of pregnancy (RR 1.39, 95% CI 0.96 to 2.01, 4 studies, 955 women), although the CIs for hypertensive disorders of pregnancy also indicated probiotics may have no effect. There were few differences between groups for other primary outcomes. Probiotics make little to no difference in the risk of caesarean section (RR 1.00, 95% CI 0.86 to 1.17; 6 studies, 1520 women; high-certainty evidence), and probably make little to no difference in maternal weight gain during pregnancy (MD 0.30 kg, 95% CI -0.67 to 1.26; 4 studies, 853 women; moderate-certainty evidence). Probiotics probably make little to no difference in the incidence of large-for-gestational age infants (RR 0.99, 95% CI 0.72 to 1.36; 4 studies, 919 infants; moderate-certainty evidence) and may make little to no difference in neonatal adiposity (2 studies, 320 infants; data not pooled; low-certainty evidence). One study reported adiposity as fat mass (MD -0.04 kg, 95% CI -0.12 to 0.04), and one study reported adiposity as percentage fat (MD -0.10%, 95% CI -1.19 to 0.99). We do not know the effect of probiotics on perinatal mortality (RR 0.33, 95% CI 0.01 to 8.02; 3 studies, 709 infants; low-certainty evidence), a composite measure of neonatal morbidity (RR 0.69, 95% CI 0.36 to 1.35; 2 studies, 623 infants; low-certainty evidence), or neonatal hypoglycaemia (mean RR 1.15, 95% CI 0.69 to 1.92; 2 studies, 586 infants; low-certainty evidence). No included studies reported on perineal trauma, postnatal depression, maternal and infant development of diabetes or neurosensory disability.

Authors' Conclusions: Low-certainty evidence from six trials has not clearly identified the effect of probiotics on the risk of GDM. However, high-certainty evidence suggests there is an increased risk of pre-eclampsia with probiotic administration. There were no other clear differences between probiotics and placebo among the other primary outcomes. The certainty of evidence for this review's primary outcomes ranged from low to high, with downgrading due to concerns about substantial heterogeneity between studies, wide CIs and low event rates. Given the risk of harm and little observed benefit, we urge caution in using probiotics during pregnancy. The apparent effect of probiotics on pre-eclampsia warrants particular consideration. Eight studies are currently ongoing, and we suggest that these studies take particular care in follow-up and examination of the effect on pre-eclampsia and hypertensive disorders of pregnancy. In addition, the underlying potential physiology of the relationship between probiotics and pre-eclampsia risk should be considered.
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April 2021

Fetal ultrasound scans to guide management of gestational diabetes: Improved neonatal outcomes in routine clinical practice.

Diabetes Res Clin Pract 2021 Mar 13;173:108696. Epub 2021 Feb 13.

Women's & Newborn Services, Royal Brisbane & Women's Hospital, Cnr Butterfield St and Bowen Bridge Rd, Herston, Queensland 4029, Australia; Faculty of Medicine, The University of Queensland, Mayne Medical Building, 288 Herston Road, Herston, Queensland 4006, Australia.

Aims: Some guidelines recommend altering glycemic targets in gestational diabetes mellitus (GDM) based on ultrasound measurements of fetal growth, but the impact on outcomes in clinical practice is unknown. The aim of this study was to compare the effects of ultrasound-guided and non-ultrasound-guided management on neonatal outcomes.

Methods: This was a retrospective, observational study of a random sample of women with GDM and their infants. Outcomes were compared between those who had GDM management tailored according to fetal growth and those who did not.

Results: In the sample of 221 women, 134 had documentation of ultrasound-guided management while 87 did not. There was no significant difference in size-for-gestational age between groups. Fewer neonates in the ultrasound-guided management group were admitted to the Special Care or Intensive Care Nursery (29.1% vs. 48.3%, P = 0.004), had a prolonged hospital stay (3.7% vs. 13.8%, P = 0.006), or had hypoglycemia after birth (42.5% vs. 56.3%, P = 0.045). The reduction in admission rates and prolonged hospital stays remained significant after controlling for confounding variables.

Conclusions: Ultrasound-guided management was independently associated with improvements in some neonatal outcomes.
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March 2021

Characteristics and in-hospital outcomes of patients requiring aeromedical retrieval for pregnancy, compared to non-retrieved metropolitan cohorts.

Aust N Z J Obstet Gynaecol 2021 Jan 10. Epub 2021 Jan 10.

Australian National University Medical School, College of Health and Medicine, The Australian National University, Canberra, Australian Capital Territory, Australia.

Background: Limited access to obstetrics and gynaecology (O&G) services in rural and remote Australia is believed to contribute to suboptimal birth outcomes.

Aims: To describe the characteristics of pregnancy aeromedical transfers, in-hospital outcomes, and patient access to O&G services, as compared to whole of Australia data.

Materials And Methods: We conducted a cohort study of women who required aeromedical retrieval for pregnancy-related issues between the 1 January 2015 and 31 December 2017.

Results: Hospital outcome data were collected on 2171 (65.2%) mothers and 2438 (100.0%) babies. The leading retrieval reason was threatened preterm labour and delivery (n = 883; 40.7%). Most patients were retrieved from rural and remote areas (n = 2224; 93.0%). Retrieved patients were significantly younger (28.0 vs 30.0 years, 95% CI 27.7-28.3), more likely to be overweight or obese (52.2% vs 45.1%, 95% CI 47.5-56.9) and to have smoked during their pregnancy (14.0% vs 9.9%, 95% CI 12.5-15.5) compared to Australian pregnant women overall. Over one-third of transferred women gave birth by Caesarean section (n = 812; 37.4%); the median gestational age at birth was 33.0 (95% CI 32.7-33.3) weeks. Early gestation is associated with low birth weights (median = 2579.5 g; 95% CI 2536.1-2622.9), neonatal resuscitation (35.4%, 95% CI 33.5-37.3), and special care nursery admission (41.2%, 95% CI 39.3-43.2). There were 42 (1.7%, 95% CI 1.2-2.2) stillbirths, which was significantly higher than seen Australia-wide (n = 6441; 0.7%).

Conclusion: This study found that pregnant women retrieved by the Royal Flying Doctor Service were younger, with higher rates of obesity and smoking.
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January 2021

Flow-induced crystallisation of polymers from aqueous solution.

Nat Commun 2020 07 6;11(1):3372. Epub 2020 Jul 6.

Department of Chemistry, The University of Sheffield, Sheffield, S3 7HF, UK.

Synthetic polymers are thoroughly embedded in the modern society and their consumption grows annually. Efficient routes to their production and processing have never been more important. In this respect, silk protein fibrillation is superior to conventional polymer processing, not only by achieving outstanding physical properties of materials, such as high tensile strength and toughness, but also improved process energy efficiency. Natural silk solidifies in response to flow of the liquid using conformation-dependent intermolecular interactions to desolvate (denature) protein chains. This mechanism is reproduced here by an aqueous poly(ethylene oxide) (PEO) solution, which solidifies at ambient conditions when subjected to flow. The transition requires that an energy threshold is exceeded by the flow conditions, which disrupts a protective hydration shell around polymer molecules, releasing them from a metastable state into the thermodynamically favoured crystalline state. This mechanism requires vastly lower energy inputs and demonstrates an alternative route for polymer processing.
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July 2020

Exercise maintains blood-brain barrier integrity during early stages of brain metastasis formation.

Biochem Biophys Res Commun 2015 Aug 5;463(4):811-7. Epub 2015 Jun 5.

Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, 1011 NW 15th, St., Miami, FL 33136, USA; Jerzy Kukuczka Academy of Physical Education, ul. Mikołowska 72a, Katowice 40-065, Poland. Electronic address:

Tumor cell extravasation into the brain requires passage through the blood-brain barrier, which is a highly protected microvascular environment fortified with tight junction (TJ) proteins. TJ integrity can be regulated under physiological and pathophysiological conditions. There is evidence that exercise can modulate oxidation status within the brain microvasculature and protect against tumor cell extravasation and metastasis formation. In order to study these events, mature male mice were given access to voluntary exercise on a running wheel (exercise) or access to a locked wheel (sedentary) for five weeks. The average running distance was 9.0 ± 0.2 km/day. Highly metastatic tumor cells (murine Lewis lung carcinoma) were then infused into the brain microvasculature through the internal carotid artery. Analyses were performed at early stage (48 h) and late stage (3 weeks) post tumor cell infusion. Immunohistochemical analysis revealed fewer isolated tumor cells extravasating into the brain at both 48 h and 3 weeks post surgery in exercised mice. Occludin protein levels were reduced in the sedentary tumor group, but maintained in the exercised tumor group at 48 h post tumor cell infusion. These results indicate that voluntary exercise may participate in modulating blood-brain barrier integrity thereby protecting the brain during metastatic progression.
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August 2015