Preterm infants are susceptible to hyperglycaemia and hypoglycaemia, which may lead to adverse neurodevelopment. The use of continuous glucose monitoring (CGM) devicesmight help in keeping glucose levels in the normal range, and reduce the need for blood sampling. However, the use of CGM might be associated with harms in the preterm infant. To assess the benefits and harms of CGM versus intermittent modalities to measure glycaemia in preterm infants 1. at risk of hypoglycaemia or hyperglycaemia; 2. with proven hypoglycaemia; or 3. with proven hyperglycaemia. We searched CENTRAL (2021, Issue 4); PubMed; Embase; and CINAHL in April2021. We also searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomized controlled trials (RCTs) and quasi-RCTs. We included RCTs and quasi-RCTs comparing the use of CGM versus intermittent modalities to measure glycaemia in preterm infants at risk of hypoglycaemia or hyperglycaemia; with proven hypoglycaemia; or with proven hyperglycaemia. We assessed the methodological quality of included trials using Cochrane Effective Practice and Organisation of Care Group (EPOC) criteria (assessing randomization, blinding, loss to follow-up, and handling of outcome data). We evaluated treatment effects using a fixed-effect model with risk ratio (RR) with 95% confidence intervals (CI) for categorical data and mean, standard deviation (SD), and mean difference (MD) for continuous data. We used the GRADE approach to assess the certainty of the evidence. We included four trials enrolling 300infants in our updated review. We included one new study and excluded another previously included study (because the inclusion criteria of the review have been narrowed). Wecomparedthe use ofCGM to intermittent modalities in preterm infantsat risk of hypoglycaemia or hyperglycaemia; however, one of these trialswas analyzedseparately because CGMwas used as a standalone device, without being coupled to a control algorithm as in the other trials.We identified no studies in preterm infants with provenhypoglycaemia orhyperglycaemia. None of the four included trials reported the neurodevelopmental outcome (i.e. the primary outcome of this review), or seizures. The effect of the use of CGM on mortality during hospitalization is uncertain (RR 0.59,95% CI 0.16 to 2.13; RD -0.02, 95% CI -0.07to 0.03; 230 participants; 2studies; very low-certainty evidence). The certaintyof the evidence was very low for all outcomesbecause of limitations in study design, and imprecision of estimates. One studyisongoing (estimated sample size 60 infants) and planned to be completed in 2022. There is insufficient evidence to determine if CGM affects preterm infant mortality or morbidities. We are very uncertain of the safety of CGM and the available management algorithms, and many morbidities remain unreported. Preterminfants at risk of hypoglycaemia or hyperglycaemiawere enrolled in all four included studies. No studies have been conducted in preterm infants with provenhypoglycaemia orhyperglycaemia. Long-term outcomeswerenot reported.Events of necrotizing enterocolitis,reported in the study published in 2021, were lower in the CGM group. However, the effect of CGM on this outcome remains very uncertain. Clinical trials are required to determine the most effective CGM and glycaemic management regimens in preterm infants before larger studies can be performed to assess the efficacy of CGM for reducing mortality, morbidity, and long-term neurodevelopmental impairments.