Effectiveness and acceptability of metformin in preventing the onset of type 2 diabetes after gestational diabetes in postnatal women: a protocol for a randomised, placebo-controlled, double-blind feasibility trial—Optimising health outcomes with Metformin to prevent diAbetes After pregnancy (OMAhA)

Research output: Contribution to journalArticlepeer-review


  • Chiamaka Esther Amaefule
  • Angeliki Bolou
  • Zoe Drymoussi
  • Francisco Jose Gonzalez Carreras
  • Maria Del Carmen Pardo Llorente
  • Doris Lanz
  • Julie Dodds
  • Lorna Sweeney
  • Elena Pizzo
  • Maria D'Amico
  • Amy Thomas
  • James Heighway
  • Jahnavi Daru
  • Soha Sobhy
  • John Robson
  • Anita Sanghi
  • Javier Zamora
  • Angela Harden
  • Graham Hitman
  • Khalid Khan
  • Teresa Pérez
  • Mohammed Sb Huda

Colleges, School and Institutes

External organisations

  • Royal Marsden Hospital, London
  • Unit for Cystic Fibrosis, Ramon y Cajal University Hospital, Madrid, Spain.
  • Queen Mary University
  • University of Greenwich
  • Barts Health NHS Trust
  • University of East London
  • Complutense University of Madrid
  • University College London Hospitals NHS Foundation Trust


INTRODUCTION: Up to half of all women diagnosed with gestational diabetes mellitus develop type 2 diabetes within 5 years after delivery. Metformin is effective in preventing type 2 diabetes in high-risk non-pregnant individuals, but its effect when commenced in the postnatal period is not known. We plan to assess the feasibility of evaluating metformin versus placebo in minimising the risk of dysglycaemia including type 2 diabetes after delivery in postnatal women with a history of gestational diabetes through a randomised trial.

METHODS AND ANALYSIS: Optimising health outcomes with Metformin to prevent diAbetes After pregnancy (OMAhA) is a multicentre placebo-controlled double-blind randomised feasibility trial, where we will randomly allocate 160 postnatal women with gestational diabetes treated with medication to either metformin (intervention) or placebo (control) tablets to be taken until 1 year after delivery. The primary outcomes are rates of recruitment, randomisation, adherence and attrition. The secondary outcomes are maternal dysglycaemia, cost and quality of life outcomes in both arms, and acceptability of the study and intervention, which will be evaluated through a nested qualitative study. Feasibility outcomes will be summarised using descriptive statistics, point estimates and 95% CIs.

ETHICS AND DISSEMINATION: The OMAhA study received ethics approval from the London-Brent Research Ethics Committee (18/LO/0505). Trial findings will be published in a peer-reviewed journal, disseminated at conferences, through our Patient and Public Involvement advisory group (Katie's Team) and through social media platforms.


Bibliographic note

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.


Original languageEnglish
Pages (from-to)e036198
JournalBMJ open
Issue number5
Publication statusPublished - 17 May 2020


  • Diabetes Mellitus, Type 2/prevention & control, Diabetes, Gestational/prevention & control, Feasibility Studies, Female, Humans, London, Metformin/therapeutic use, Multicenter Studies as Topic, Outcome Assessment, Health Care, Pregnancy, Quality of Life, Randomized Controlled Trials as Topic

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