Santamaria 2016.

Study characteristics
Methods	Study type: parallel, open‐label RCT
Participants	220 overweight non‐obese pregnant women from Italy. Inclusion criteria: pre‐pregnancy BMI > 25 and < 30 kg/m2, first trimester fasting plasma glucose ≤ 126 mg/dL and/or random glycaemia < 200 mg/dL, single gestation, Caucasian ethnicity.  Women were 12 to13 weeks' gestation at study entry. Exclusion criteria: pre‐pregnancy BMI < 25 and ≥ 30 kg/m2, previous GDM, pre‐gestational diabetes, first trimester glycosuria (urine glucose value 10 mg/dL or greater), treatment with corticosteroids. Location: obstetric departments of 2 university hospitals located in Messina and Modena, Italy Timeframe: January 2012 to December 2014
Interventions	Intervention: 4 g myo‐inositol plus 400 mg folic acid daily (2 g myo‐inositol + 200 mg folic acid orally twice a day), (N = 110) Duration of myo‐inositol supplementation: from trial entry until the end of pregnancy Comparison: 400 mg folic acid daily (200 mg folic acid orally twice a day), (N = 110)
Outcomes	Maternal: occurrence of gestational diabetes, rate of caesarean section, pregnancy induced hypertension, occurrence of side effects, Homeostasis Model Assessment‐Insulin Resistance index (HOMA‐IR) Criteria used to diagnose gestational diabetes: IADPSG Neonatal: fetal macrosomia (birthweight > 4000 g), preterm delivery (< 37 weeks), shoulder dystocia, neonatal hypoglycaemia, transfer to NICU
Notes	Sample size calculation: yes Funding source: none, the women bought the supplement on their own Conflicts of interest: none reported ClinicalTrials.gov trial registration NCT01047982 Further information was received following email contact with the authors. This trial was conducted at the same time as the D'Anna 2015 trial, with women being recruited to the appropriate trial depending on eligibility criteria.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation list was obtained by using a computer‐generated random allocation
Allocation concealment (selection bias)	Low risk	The allocations were sealed in numbered white envelopes, which were kept in the midwifery facility.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Abstract states "open‐label" Personnel were not blinded: "because of the design of the study, the gynaecologist knew the group allocation of the patient".
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention is made of blinding of outcome assessors, although primary outcome of occurrence of GDM is objective and based on laboratory results.
Incomplete outcome data (attrition bias) All outcomes	Low risk	110 women were initially recruited to each group. 15 women were excluded from the myo‐inositol group (one mid‐trimester miscarriage, 2 abandoned the trial not attending the OGTT, 5 delivered elsewhere, and 7 dropped out). Analysis was performed on the remaining 95 women. 8 women were excluded from the placebo group (one mid‐trimester miscarriage, 2 abandoned the trial not attending the OGTT, and 5 delivered elsewhere). Analysis was performed on the remaining 102 women.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes are reported on.
Other bias	Low risk	Appears free of other bias. The authors reported no potential conflicts of interest.