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Effects of treatment in women with gestational diabetes mellitus: systematic review and meta-analysis

BMJ 2010; 340 doi: (Published 01 April 2010) Cite this as: BMJ 2010;340:c1395
  1. Karl Horvath, project manager EBM review center1, head of outpatient facility diabetes and metabolism2,
  2. Klaus Koch, project manager3,
  3. Klaus Jeitler, scientific assistant1,
  4. Eva Matyas, scientific assistant1,
  5. Ralf Bender, head of department of medical biometry3,
  6. Hilda Bastian, head of department of health information3,
  7. Stefan Lange, deputy director3,
  8. Andrea Siebenhofer, professor for chronic care and health services research4, project manager1
  1. 1EBM Review Center, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria
  2. 2Division of Endocrinology and Nuclear Medicine, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15
  3. 3Institute for Quality and Efficiency in Health Care (IQWiG), Dillenburger Str. 27, 51105 Cologne, Germany
  4. 4Institute of General Practice, Goethe University, Frankfurt, Germany
  1. Correspondence to: K Horvath Karl.Horvath{at}
  • Accepted 22 January 2010


Objective To summarise the benefits and harms of treatments for women with gestational diabetes mellitus.

Design Systematic review and meta-analysis of randomised controlled trials.

Data sources Embase, Medline, AMED, BIOSIS, CCMed, CDMS, CDSR, CENTRAL, CINAHL, DARE, HTA, NHS EED, Heclinet, SciSearch, several publishers’ databases, and reference lists of relevant secondary literature up to October 2009.

Review methods Included studies were randomised controlled trials of specific treatment for gestational diabetes compared with usual care or “intensified” compared with “less intensified” specific treatment.

Results Five randomised controlled trials matched the inclusion criteria for specific versus usual treatment. All studies used a two step approach with a 50 g glucose challenge test or screening for risk factors, or both, and a subsequent 75 g or 100 g oral glucose tolerance test. Meta-analyses did not show significant differences for most single end points judged to be of direct clinical importance. In women specifically treated for gestational diabetes, shoulder dystocia was significantly less common (odds ratio 0.40, 95% confidence interval 0.21 to 0.75), and one randomised controlled trial reported a significant reduction of pre-eclampsia (2.5 v 5.5%, P=0.02). For the surrogate end point of large for gestational age infants, the odds ratio was 0.48 (0.38 to 0.62). In the 13 randomised controlled trials of different intensities of specific treatments, meta-analysis showed a significant reduction of shoulder dystocia in women with more intensive treatment (0.31, 0.14 to 0.70).

Conclusions Treatment for gestational diabetes, consisting of treatment to lower blood glucose concentration alone or with special obstetric care, seems to lower the risk for some perinatal complications. Decisions regarding treatment should take into account that the evidence of benefit is derived from trials for which women were selected with a two step strategy (glucose challenge test/screening for risk factors and oral glucose tolerance test).


  • We thank P T Sawicki for repeated reviewing of the data and manuscript; S Droste and S Waffenschmidt for assistance with the literature search strategies; A Steinzen, M Messer, and Y Zens for help with literature screening; and E Vervölgyi, C Schürmann, and S Sturtz for help with additional analyses.

  • Contributors: All authors contributed to the writing of the study protocol, and the interpretation of data. They also contributed in drafting the article or in revising it critically for important intellectual content and approved the final version. KH, KK, and AS are guarantors. M Häusler contributed as a specialist in obstetrics and gynaecology in preparing the original IQWiG report. U Pueringer helped in collecting data.

  • Funding: This study was commissioned by the German Federal Joint Committee. KH, KJ, EM, and AS acted as consultants for the preparation of the review. For this they were reimbursed by IQWiG. KK, RB, HB, and SL (as well as PTS, SD, SW, AS, MM, YZ, EV, CS, and SS) are employees of IQWiG.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare that all authors (KH, KK, KJ, EM, RB, HB, SL, AS) have no support from any company for the submitted work, have no relationship with companies that might have an interest in the submitted work in the previous 3 years; their spouses, partners or children have no financial relationship that may be relevant to the submitted work; and have no non-financial interests that may be relevant to the submitted work.

  • Ethical approval: Not required.

  • Data sharing: The search strategy and detailed information on further maternal and neonatal outcomes for studies from both pools can be found at

  • Accepted 22 January 2010

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