Antenatal Magnesium for Preterm Delivery Reduces Risk of Cerebral Palsy

[EBNEO]

We would like to promote one of our latest reviews, on antenatal magnesium for preterm delivery and risk of cerebral palsy.

You find the full review on our web site, ebneo.org

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The current American College of Obstetricians and Gynecologists (ACOG) Committee Opinion supports the use of magnesium sulfate for fetal neuroprotection before 32 weeks of gestation. The clinical trial reviewed here is the largest and most recent to inform these guidelines. This randomized control trial (RCT), aimed to determine if the administration of magnesium sulfate to women at high risk of preterm delivery would reduce the risk of cerebral palsy (CP), found a reduction in moderate/severe CP at 2 years of age following antenatal magnesium sulfate exposure (RR 0.55, 95% CI 0.32-0.95).  These results were consistent with previous RCTs primarily evaluating the neuroprotective benefits of magnesium sulfate on the incidence of CP in preterm infants. Additionally, a Cochrane review concluded that 63 women were needed to prevent one diagnosis of CP.

Further investigation is warranted to provide updated and unified guidelines regarding the use of magnesium sulfate for fetal neuroprotection. There was significant heterogeneity in treatment regimens between RCTs with no trial sharing the same loading dose, treatment dose, duration of dosing, or retreatment regimen of magnesium sulfate. Additionally, although no serious maternal complications of antenatal magnesium exposure have been reported, there were several minor complications, including a 50% increase in maternal hypotension, leading to a 3.2-fold increase in cessation of therapy. Optimal treatment regimens would likely lead to a refined understanding of treatment effect size, better protocol adherence, and ultimately improved neurodevelopmental outcomes.

The results of this trial should be considered in light of advances in neonatal medicine affecting neurodevelopmental outcomes. For example, during the time of this study’s enrollment, the American Academy of Pediatrics (AAP) recommended against routine use of postnatal corticosteroids in preterm infants because of its negative effect on neurodevelopmental outcomes. This recommendation significantly curtailed the use of early postnatal steroids, potentially altering neurodevelopmental outcomes if differed between treatment groups. Second, there has been increased survival of infants 22-23 weeks of gestation. Currently, there are no RCTs that investigate the neuroprotective benefit of magnesium sulfate in <24 weeks of gestation.

It has been 20 years since recruitment started and nearly 10 years since the publication of this landmark trial has influenced the practice of obstetricians in the United States. In that same time, there continue to be advances in the care of the extremely low birth weight infants allowing for changes in survival and neurodevelopmental outcomes. Although many institutions follow ACOG recommendations of administering antenatal magnesium sulfate in preterm delivery, there are no recommendations for magnesium sulfate treatment regimens or gestational age thresholds presumably leading to a variety of clinical practices. Perhaps it is time to repeat this clinical trial in a new era to help elucidate both the optimal treatment regimen as well as the effect of antenatal magnesium exposure in the setting of preterm labor and delivery on neurodevelopmental outcomes. In the meantime, this trial remains consistent with available evidence supporting antenatal magnesium sulfate exposure in preterm infants to reduce cerebral palsy.