Bevier 1999.

Methods	Randomised controlled trial.
Participants	103 women with a positive 50 g 1‐hour GCT (> 140 mg/dl) but a negative 100 g 3‐hour OGTT according to the National Diabetes Data Group (NDDG) criteria (see notes). Exclusion criteria: women with evidence of hypertension, collagen disease, chronic renal disease, cardiac or pulmonary disease, Rh sensitisation, or a history of preterm labor or SGA infants. Setting: Santa Barbara, California, USA.
Interventions	Women in the intervention group (n = 35) Dietary counselling: 30 kcal/kg/day if woman was 80‐120% of ideal body weight; or 24 kcal/kg/day if woman was greater than 120% of ideal body weight; diet consisted of 40% carbohydrate, 20% protein, and 40% fat, broken into 3 meals and 3 snacks. Home blood glucose monitoring (HBGM) instruction: checking the fasting and the 1‐hr postprandial BGL, using visual reagent strips. Weekly HBGM diary to clinic. Weekly random BGL at clinic. Weekly reinforcement of prescribed diet. Insulin therapy when fasting BGL > 90 mg/dl or the 1‐hr BGL > 120 mg/dl on 3 or more occasions. Women in the control group (n = 48) Random BGL during regular clinic visits. Insulin therapy when the random result > 120 mg/dl. All women had haemoglobin A1c (HbA1c) measurement at 28 and 32  weeks.
Outcomes	Maternal HbA1c level, pre‐eclampsia, mode of birth, delivery complications (shoulder dystocia, tight nuchal cord, meconium, prolonged labor phase, abnormal fetal heart rate), gestational age at birth, Apgar score at 1 min and 5 min, birthweight, infant haemoglobin, glucose, haematocrit, morbidities, and congenital anomalies.
Notes	The NDDG criteria (adopted by ADA and ACOG at the time of study) Fasting: > 105 mg/dl (5.8 mmol/l). 1‐h: > 190 mg/dl (10.6 mmol/l). 2‐h: > 165 mg/dl (9.2 mmol/l). 3‐h: > 145 mg/dl (8.1 mmol/l). 2 or more of the values must be met or exceeded for GDM diagnosis.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as women were randomly assigned to either experimental or control groups.
Allocation concealment (selection bias)	Unclear risk	No information was given on allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Prenatal care and deliveries were performed by six obstetricians who were not blinded to the mothers treatment group. Participants were unlikely to be blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information on whether outcome assessors were blinded or not.
Incomplete outcome data (attrition bias) All outcomes	High risk	A total of 20 women (19.4%) were excluded post randomisation 5 women (4 in control group, 1 in experimental group) required insulin. 1 women had a therapeutic abortion. 14 women were noncompliant to allocated treatment (i.e. women in the intervention group did not adhere to intervention or women in the control group received diet counselling and/or home blood glucose monitoring instructions). 83 women (45 in the control group and 35 in the intervention group) were included in analysis.
Selective reporting (reporting bias)	High risk	There was no clear definition on macrosomia. Published data on macrosomia was unclear, and cannot be included in the meta‐analysis of macrosomia.
Other bias	Low risk	No obvious risk of other bias.