MAGENTA Trial

Babies born very preterm have a greater risk of significant neurological impairments such as cerebral palsy, and the risk of complications increases the earlier the baby is born. The MAGENTA Trial aimed to assess whether giving magnesium sulphate compared to placebo to women immediately prior to preterm birth between 30 and 34 weeks’ gestation would reduce the risk of death or cerebral palsy in their children at 2 years’ corrected age.

Recruitment for this study was completed in 2018, with mothers and babies taking part across 24 tertiary maternity hospitals in Australia and New Zealand. Eligible women were randomly allocated to receive either magnesium sulphate or placebo.

Women in the magnesium sulphate group were given 50ml of a 100ml infusion bag containing 8g magnesium sulphate heptahydrate (equivalent to 4g magnesium sulphate heptahydrate). Women in the placebo group were given 50ml of a 100ml infusion bag containing isotonic sodium chloride solution (0.9% sodium chloride). Both treatments were administered through a dedicated intravenous infusion line over 30 minutes.

All surviving children had a paediatric and psychological assessment done at 2 years’ corrected age.

Overall, the chances of the child surviving without cerebral palsy at two years of age were similar whether their mother received magnesium sulphate or the saline placebo (97.2% versus 97.6%).

The health of the children was also similar between the groups for all the assessments for sight, hearing, language and cognitive development, height and weight. There was some suggestion that children whose mothers were given magnesium sulphate may have more behavioural problems (10% versus 6%).

As newborns, babies whose mothers had been given magnesium sulphate were less likely to develop breathing problems (34% versus 41%) and were less likely to require long-term oxygen support (5.6% versus 8.2%).

These findings provide helpful evidence to guide the care of women at risk of preterm birth at 30 to 34 weeks’ gestation. The results will be available to health professionals caring for mothers and their babies, have been used to update the associated Cochrane review and will be used to update the guidelines for use of magnesium sulphate prior to preterm birth in Australia and New Zealand.

If you participated in the MAGENTA Trial and have questions, please email us at magenta@auckland.ac.nz.

Crowther CA, Ashwood P, Middleton PF, et al. Prenatal Intravenous Magnesium at 30-34 Weeks’ Gestation and Neurodevelopmental Outcomes in Offspring: The MAGENTA Randomized Clinical Trial. JAMA. 2023;330(7):603–614. doi:10.1001/jama.2023.12357

Crowther, CA; Middleton, PF; Wilkinson, D; Ashwood, P; Haslam, R; and the MAGENTA Study Group. Magnesium sulphate at 30 to 34 weeks’ gestational age: neuroprotection trial (MAGENTA) - study protocol BMC Pregnancy and Childbirth. 2013.

Shepherd ES, Goldsmith S, Doyle LW, Middleton P, Marret S, Rouse DJ, Pryde P, Wolf HT, Crowther CA. Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus. Cochrane Database Syst Rev. 2024 May 10;5(5):CD004661. doi: 10.1002/14651858.CD004661.pub4. PMID:

Shepherd ES, Goldsmith S, Doyle LW, Middleton P, Marret S, Rouse DJ, Pryde P, Wolf HT, Crowther CA. Magnesium Sulfate Before Preterm Birth for Neuroprotection: An Updated Cochrane Systematic Review. Obstet Gynecol. 2024 Aug 1;144(2):161-170. doi: 10.1097/AOG.0000000000005644. Epub 2024 Jun 3. PMID: 38830233; PMCID: PMC11250087. DOI: 10.1097/AOG.0000000000005644