Intended for healthcare professionals

Research

Effectiveness of continuous glucose monitoring in pregnant women with diabetes: randomised clinical trial

BMJ 2008; 337 doi: https://doi.org/10.1136/bmj.a1680 (Published 25 September 2008) Cite this as: BMJ 2008;337:a1680
  1. Helen R Murphy, senior research fellow1,
  2. Gerry Rayman, consultant physician1,
  3. Karen Lewis, diabetes research nurse1,
  4. Susan Kelly, diabetes specialist midwife2,
  5. Balroop Johal, consultant obstetrician3,
  6. Katherine Duffield, diabetes nurse specialist4,
  7. Duncan Fowler, consultant physician1,
  8. Peter J Campbell, clinical research fellow5,
  9. Rosemary C Temple, consultant physician4
  1. 1Department of Diabetes and Endocrinology, Ipswich Hospital NHS Trust, Ipswich IP4 5PD
  2. 2Departments of Diabetes and Obstetrics, Ipswich Hospital NHS Trust
  3. 3Department of Obstetrics, Ipswich Hospital NHS Trust
  4. 4Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospital NHS Trust, Norwich
  5. 5Wellcome Trust Sanger Institute, Cambridge
  1. Correspondence to: H R Murphy Helen.Murphy{at}ipswichhospital.nhs.uk
  • Accepted 5 August 2008

Abstract

Objective To evaluate the effectiveness of continuous glucose monitoring during pregnancy on maternal glycaemic control, infant birth weight, and risk of macrosomia in women with type 1 and type 2 diabetes.

Design Prospective, open label randomised controlled trial.

Setting Two secondary care multidisciplinary obstetric clinics for diabetes in the United Kingdom.

Participants 71 women with type 1 diabetes (n=46) or type 2 diabetes (n=25) allocated to antenatal care plus continuous glucose monitoring (n=38) or to standard antenatal care (n=33).

Intervention Continuous glucose monitoring was used as an educational tool to inform shared decision making and future therapeutic changes at intervals of 4-6 weeks during pregnancy. All other aspects of antenatal care were equal between the groups.

Main outcome measures The primary outcome was maternal glycaemic control during the second and third trimesters from measurements of HbA1c levels every four weeks. Secondary outcomes were birth weight and risk of macrosomia using birthweight standard deviation scores and customised birthweight centiles. Statistical analyses were done on an intention to treat basis.

Results Women randomised to continuous glucose monitoring had lower mean HbA1c levels from 32 to 36 weeks’ gestation compared with women randomised to standard antenatal care: 5.8% (SD 0.6) v 6.4% (SD 0.7). Compared with infants of mothers in the control arm those of mothers in the intervention arm had decreased mean birthweight standard deviation scores (0.9 v 1.6; effect size 0.7 SD, 95% confidence interval 0.0 to 1.3), decreased median customised birthweight centiles (69% v 93%), and a reduced risk of macrosomia (odds ratio 0.36, 95% confidence interval 0.13 to 0.98).

Conclusion Continuous glucose monitoring during pregnancy is associated with improved glycaemic control in the third trimester, lower birth weight, and reduced risk of macrosomia.

Trial registration Current Controlled Trials ISRCTN84461581.

Footnotes

  • We thank the women who participated, Medtronic UK for donating study equipment, and coinvestigators Katharine Stanley, Sue Land, Nicoletta Dozio (Norwich UK), and Damian Morris (Ipswich UK) for comments on the manuscript.

  • Contributors: HRM, GR, PJC, and RCT designed the study, interpreted the data, and wrote the manuscript. KL, KD, SK, BJ, and DF researched the data, contributed to the discussion, and reviewed or edited the manuscript. HRM, GR, and RCT are guarantors.

  • Funding: This was an investigator initiated study funded by the Ipswich Diabetes Centre Charity Research Fund. HRM also received salary support from Diabetes UK. The study equipment (6 x CGMS Gold monitors and 300 sensors) was donated free of charge by Medtronic UK. The research was sponsored by Ipswich Hospital NHS Trust and was independent of all the study funders.

  • Competing interests: HRM and GR have received honorariums for speaking at research symposiums sponsored by Medtronic in 2004 and 2005.

  • Ethical approval: Suffolk and Norfolk local research ethics committees.

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

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

View Full Text