Introduction: The risk for brain injury manifested as cerebral palsy is higher in very preterm born children than in term. Prenatal administration of magnesium sulfate (MgSO4) has been shown to be neuroprotective and reduces the proportion of very preterm born children later diagnosed with cerebral palsy. A Swedish national clinical practice guideline was implemented in March 2020, stipulating the administration of a single intravenous dose of 6 g MgSO4 1-24 h prior to delivery before gestational age 32+ 0, aiming for 90% treatment coverage. The aim of this study was to evaluate the feasibility of this new clinical practice guideline in the first year of its implementation. Material and methods: Data on MgSO4 treatment were collected by reviewing the medical charts of women who gave birth to live born children in gestational age 22+ 0-31+ 6 during the period of March 1, 2020 to February 28, 2021, at five Swedish university hospitals. Women with pre-eclampsia, eclampsia, or high elevated liver enzymes low platelets (HELLP) were excluded. Results: A total of 388 women were eligible and 79% received treatment with MgSO4. Of the 21% not receiving treatment, 9% did not receive treatment due to lack of knowledge about the clinical practice guideline, 9% were not possible to treat and 3% had missing data. The proportion treated increased from 72% to 87% from the first to the last 3 months. Of those treated, 81% received the drug within the stipulated timeframe (mean 8.7 h, median 3.4 h). Conclusions: There was a positive trend over time in the proportion of women receiving MgSO4 treatment, but the a priori target of 90% was not reached during the first year of implementation. Our findings indicate that this target could be reached with additional information to clinicians.