PICO for study inclusion
| Population (P) | Intervention (I) | Comparison (C) | Outcomes (O) | |
| Inclusion | Pregnant women of any age, ethnicity, socioeconomic status, geographic area, comorbidity or gestational age | Metformin administered in any form and route, alone or combined with other intervention/s, of any dosage and for any duration | Placebo, usual care and/or other pharmacological or non-pharmacological interventions including insulin, lifestyle intervention/s or other oral hypoglycaemic agents (sulfonylureas, acarbose, glibenclamide/glyburide) | Primary maternal outcomes: glycaemic control (glucose, insulin, HbA1c); incidence of GDM* and/or hyper/hypoglycaemia* Primary neonatal outcomes: hypoglycaemia*, birth weight, birth length, head circumference and gestational age at delivery Secondary outcomes: other maternal, birth and neonatal outcomes including miscarriage, birth defects, GWG, pre-eclampsia/eclampsia, LGA/macrosomia, SGA and PTB (see full list in online supplementary material) |
| Exclusion | Studies in non-pregnant populations | Studies without a metformin therapy arm | Studies without a control or comparison arm | Studies without clinical outcomes (mechanistic studies) |
| Study type | RCTs and systematic reviews of RCTs | |||
| Language | No limit | |||
| Year of publication | No limit | |||
*As defined by authors and using the criteria selected in individual studies.
GDM, gestational diabetes mellitus; GWG, gestational weight gain; HbA1c, haemoglobin A1c; LGA, large for gestational age; PTB, preterm birth; RCT, randomised controlled trial; SGA, small for gestational age.