Table 2.

Data to be extracted in aggregate and IPD format from included studies

Study	Participants	Intervention/control	Primary outcomes†	Secondary outcomes
First author and journal/source	Maternal age, parity, ethnicity and gestational age at enrolment	Metformin treatment protocols (dose, including graded dosing, frequency, duration)	Maternal glycaemic control (fasting and postprandial/postchallenge glucose; insulin; and HbA1c) at any/all timepoints	All other maternal, birth and neonatal outcomes reported in individual studies (online supplementary material)
Country and year of publication	Maternal anthropometry (BMI, weight, GWG)	Regimens for each control or comparator group	Incidence of GDM* and/or maternal hyper/hypoglycaemia*	Long-term infant/child outcomes
Study design, setting and sample size	Smoking status and use of medications, supplements or substances	Use of supplemental insulin	Incidence of neonatal hypoglycaemia*	Development of T2D (in pregnancy or post partum)
Follow-up duration	Disease status (pre-existing T2D, GDM, PCOS, and so on)	Use of other pharmacological or non-pharmacological cointerventions	Birth weight, birth length and head circumference, and gestational age at delivery*	Patient satisfaction with experience/treatment
Inclusion/exclusion and diagnostic criteria	Comorbidities, history of GDM or family history of diabetes	Number analysed per group and ITT analysis		Adverse events/side effects occurring during the study
Primary outcome*

*As defined by authors of individual studies which may be based on clinical diagnosis (separate analyses will be performed for different GDM diagnostic criteria) or in the case of gestational age, this may be based on ultrasound measurements, last menstrual cycle, self-report, and so on.

†Baseline, follow-up and delta values will be collected for all continuous primary maternal outcomes.

BMI, body mass index; GDM, gestational diabetes mellitus; GWG, gestational weight gain; HbA1c, haemoglobin A1c; IPD, individual patient data; ITT, intention to treat; PCOS, polycystic ovary syndrome; T2D, type 2 diabetes.