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

BACKGROUND

In the last 2 decades, based on systematic reviews of randomized controlled trials, antenatal magnesium sulfate has been variably implemented internationally for fetal neuroprotection.

OBJECTIVE

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 to severe functional impairment in an Australian and New Zealand cohort.

STUDY

DESIGN

This population-based retrospective cohort study, using data from the Australian and New Zealand Neonatal Network registry, included neonates born from January 1, 2012 through December 31, 2020 at <30 weeks' gestation; due to data availability, 2 to 3 years of follow-up was restricted to those born through December 31, 2017 at <28 weeks' gestation and/or weighing <1000 g. Analyses were performed using logistic regression with adjustment for potential confounding.

RESULTS

The cohort included 16,582 neonates for outcomes to hospital discharge. For primary outcomes at 2 to 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 to 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).

CONCLUSION

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 to severe functional impairment, strongly supporting ongoing and enhanced implementation.