Abstract Aim The objective of this meta‐analysis was to evaluate obstetric outcomes in gestational diabetes mellitus (GDM) patients treated with flexible management based on intrauterine ultrasound fetal growth (FMIUFG) or strict maternal glycemic adjustment (SMGA). Methods We performed a comprehensive systematic review of electronic databases for randomized clinical trials (RCTs) comparing obstetrics outcomes of singleton GDM patients managed according to FMIUFG or SMGA. The review protocol was registered in PROSPERO (CRD497888). Searches were conducted in PubMed, Embase, Cochrane, and LILACS. Primary outcomes were gestational age at delivery and birth weight. Random‐effect model meta‐analyses were used to minimize the effects of uncertainty associated with inter‐study variability. Results are reported as standardized mean differences (SMDs) or as odds ratios (ORs) and their 95% confidence interval (CI). Heterogeneity between studies was estimated using the I 2 statistic. The Cochrane Risk of Bias Scale was used to assess the quality of studies. There were five RCTs with low to moderate risk of bias, including 450 patients managed according to the FMIUFSG and 381 according to the SMGA. Results The macrosomia (birthweight >4000 g) rate was lower in pregnancies managed according to FMIUFG than SMGA adjustments (OR: 0.34; 95%CI: 0.16, 0.71). There were no significant differences in hypertensive disorder, cesarean section, neonatal intensive care unit admission, and large newborn for gestational age rates. Conclusions The macrosomia rate was lower in women managed with the FMIUFG. There were no significant differences in other obstetric and neonate outcomes.