Table 2.

Inclusion and exclusion criteria

Inclusion criteria	Exclusion criteria
1. Women diagnosed with gestational diabetes as per the National Institute for Health and Care Excellence criteria, at time of consent and who are treated with metformin and/or insulin in pregnancy.	1. Women diagnosed with pre-existing type 1 or type 2 diabetes
	2. Women with a body mass index of ≥50 kg/m2
	3. Known contraindications to metformin Hypersensitivity to metformin hydrochloride or to any of the excipients. Liver failure or liver dysfunction at the time of trial entry. Renal failure or renal dysfunction at the time of trial entry. Intravascular administration of iodinated contrast agents planned or received within 48 hours from commencing study medication, (metformin can be taken only after renal function has been re-evaluated and found to be normal.)
2. Aged 16 years or over at the time of consent.	4. Known very severe lactose intolerance
3. Able to provide written informed consent in English language.	5. Women being treated with metformin postnatally, for polycystic ovary syndrome
	6. Any acute conditions at the time of trial entry with the potential to alter renal function