Antenatal magnesium sulfate prior to very preterm birth in routine care is associated with increased survival without cerebral palsy.

Shepherd, Emily; Rumbold, Alice; McIntyre, Sarah; Goldsmith, Shona; Karim, Tasneem; Keir, Amy; Poprzeczny, Amanda; Hunt, Rod W et al. · Am J Obstet Gynecol · 2026

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Abstract

In the last 2 decades, based on systematic reviews of randomized controlled trials, antenatal magnesium sulfate has been variably implemented internationally for fetal neuroprotection. Our objective was to assess the effects of magnesium sulfate exposure prior to extremely preterm/low birthweight birth on survival without cerebral palsy or moderate-severe functional impairment in an Australian and New Zealand cohort. This population-based retrospective cohort study, using data from the Australian and New Zealand Neonatal Network registry, included neonates born from 1/1/2012 through 12/31/2020 at < 30 weeks' gestation; due to data availability, 2-3 year follow up was restricted to those born through 12/31/2017 at < 28 weeks' gestation and/or weighing < 1000 g. Analyses were performed using logistic regression with adjustment for potential confounding. The cohort included 16582 neonates for outcomes to hospital discharge. For primary outcomes at 2-3 years, among 6763 infants (4353 [64%] exposed to magnesium sulfate), exposure to magnesium sulfate was associated with a reduced risk of death or cerebral palsy (adjusted relative risk 0.83, 95% confidence interval 0.74-0.93) and of death or moderate-severe functional impairment (adjusted relative risk 0.88, 95% confidence interval 0.81-0.97). A clear reduction in cerebral palsy was observed for children born from singleton pregnancies (adjusted relative risk 0.68, 95% confidence interval 0.47-0.98). When multiples were included, the reduced risk of cerebral palsy was not statistically significant (adjusted relative risk 0.78, 95% confidence interval 0.59-1.05). Our large, binational study demonstrates real-world benefits of exposure to magnesium sulfate prior to extremely preterm and/or low birthweight birth, including increased survival without cerebral palsy or moderate-severe functional impairment, strongly supporting ongoing and enhanced implementation.