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Treatments for gestational diabetes: a systematic review and meta-analysis
  1. Diane Farrar1,
  2. Mark Simmonds2,
  3. Maria Bryant3,
  4. Trevor A Sheldon4,
  5. Derek Tuffnell5,
  6. Su Golder6,
  7. Debbie A Lawlor7
  1. 1 Bradford Institute for Health Research, Bradford Royal Infirmary, Bradford, UK
  2. 2 Centre for Reviews and Dissemination, University of York, York, UK
  3. 3 Leeds Institute of Clinical Trials Research, University of Leeds, Leeds, West Yorkshire, UK
  4. 4 Hull York Medical School, University of York, York, UK
  5. 5 Bradford Women’s and Newborn Unit, Bradford Teaching Hospitals NHS Foundation, Bradford, UK
  6. 6 Department of Health Sciences, University of York, York, UK
  7. 7 MRC Integrative Epidemiology Unit, School of Social and Community Medicine, University of Bristol, Bristol, UK
  1. Correspondence to Dr Diane Farrar; diane.farrar{at}


Objective To investigate the effectiveness of different treatments for gestational diabetes mellitus (GDM).

Design Systematic review, meta-analysis and network meta-analysis.

Methods Data sources were searched up to July 2016 and included MEDLINE and Embase. Randomised trials comparing treatments for GDM (packages of care (dietary and lifestyle interventions with pharmacological treatments as required), insulin, metformin, glibenclamide (glyburide)) were selected by two authors and double checked for accuracy. Outcomes included large for gestational age, shoulder dystocia, neonatal hypoglycaemia, caesarean section and pre-eclampsia. We pooled data using random-effects meta-analyses and used Bayesian network meta-analysis to compare pharmacological treatments (ie, including treatments not directly compared within a trial).

Results Forty-two trials were included, the reporting of which was generally poor with unclear or high risk of bias. Packages of care varied in their composition and reduced the risk of most adverse perinatal outcomes compared with routine care (eg, large for gestational age: relative risk0.58 (95% CI 0.49 to 0.68; I2=0%; trials 8; participants 3462). Network meta-analyses suggest that metformin had the highest probability of being the most effective treatment in reducing the risk of most outcomes compared with insulin or glibenclamide.

Conclusions Evidence shows that packages of care are effective in reducing the risk of most adverse perinatal outcomes. However, trials often include few women, are poorly reported with unclear or high risk of bias and report few outcomes. The contribution of each treatment within the packages of care remains unclear. Large well-designed and well-conducted trials are urgently needed.

Trial registration number PROSPERO CRD42013004608.

  • gestational diabetes
  • systematic review
  • meta-analysis
  • network analysis
  • treatments
  • packages of care
  • insulin
  • metformin
  • glibenclamide (glyburide)

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  • Contributors DF, MS, DAL and TAS designed the study. MS wrote the statistical analysis plan. DF monitored the review process. DF, MS, MB, DAL, TAS and DT interpreted the data, DF, MS, MB and SG assessed studies for inclusion. MS cleaned and analysed the data. DF wrote the draft paper. All authors have approved the final version. DF is the guarantor and takes responsibility for the content of this article.

  • Funding This work was supported by the National Institute for Health Research (NIHR), Health Technology Assessment (HTA) programme, project number 11/99/02. DF holds a NIHR Post-doctoral Research Fellowship award (PD-2014-07-019). DAL works in a Unit that is supported by the University of Bristol and UK Medical Research Council ((MC_UU_12013/5) and she holds a NIHR Senior Investigator award (NF-SI-0611-10196).The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the HTA, NIHR, MRC, UK National Health Service (NHS) or the Department of Health.

  • Competing interests All authors have completed the ICMJE uniform disclosure form at and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Patient consent Consent is not required when conducting a systematic review.

  • Ethics approval This study did not require ethical approval as the data used have been published previously, and hence are already in the public domain.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Extracted data are available upon request to the corresponding author.

  • Correction notice This paper has been amended since it was published Online First. Owing to a scripting error, some of the publisher names in the references were replaced with 'BMJ Publishing Group'. This only affected the full text version, not the PDF. We have since corrected these errors and the correct publishers have been inserted into the references.

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