Magnesium sulfate given to pregnant women may not prevent the incidence of cerebral palsy, but may reduce its severity, according to data from two U.S. clinical sites.
The findings, “Comparison of Cerebral Palsy Severity Between 2 Eras of Antenatal Magnesium Use,” were published in JAMA Pediatrics.
In the last decades, survival rates of preterm infants have increased significantly. However, preterm birth is a well-recognized risk factor for cerebral palsy.
Earlier evidence from an analysis of multiple studies suggested that treatment with magnesium sulfate, given before the 32nd week of pregnancy, could reduce the risk of cerebral palsy in premature babies.
Results from a previous Phase 3 clinical trial (NCT00014989) had also shown that treatment with magnesium sulfate could improve the survival of infants with moderate to severe cerebral palsy.
Magnesium sulfate is a mineral preparation of magnesium commonly called Epsom salt. Its use in medicine varies. It has been used for the management of severe asthma attacks and to prevent and treat the onset of seizures in women with pre-eclampsia, a disorder of pregnancy that results from a combination of high blood pressure and either large amounts of protein in the urine or other organ dysfunction.
These positive clinical results supported the decision of the American College of Obstetricians and Gynecologists to advise the use of magnesium sulfate before anticipated early preterm birth to reduce risk of cerebral palsy.
Despite these findings, the neuroprotective role of magnesium to prevent cerebral palsy remains unclear.
To further explore this issue, researchers evaluated the clinical records of all children born between 2002 and 2014 at the Ohio State University Wexner Medical Center and Nationwide Children’s Hospital in Columbus, Ohio, and who were delivered before 32 weeks of gestation.
From a total of 3,736 eligible deliveries reported, 110 infants were diagnosed with cerebral palsy. Among these cases, 57 (52%) received antenatal magnesium sulfate supplements.
Administration of magnesium sulfate had been implemented in these hospitals in 2008, which was evident by the increased number of pregnant women receiving this treatment (36% before 2008 versus 62% after 2008).
Further analysis showed that the frequency of severe cases of cerebral palsy decreased after 2008, after magnesium protocol implementation. Indeed, treatment with magnesium sulfate was associated with 64% lower risk of severe cerebral palsy.
However, researchers found that over time, more infants were diagnosed with cerebral palsy. This was mainly because of enhanced diagnosis of mild to moderate cases rather than incidence of more severe cases.
Indeed, they found that children born after 2008, and especially those born after 2012, were more likely to be diagnosed with cerebral palsy at a younger age.
“Earlier diagnosis of cerebral palsy … at our institution may be associated with advances in neonatal intensive care,” such as avoidance of postnatal steroids and systematic use of caffeine, researchers said. “But [it] may also be due to implementation of guidelines for evidence-based early recognition of cerebral palsy.”
Collectively, these results suggest that although there is a trend for a decrease in cerebral palsy severity over time, this reduction “could not be attributed to magnesium.”
Additional studies are warranted to better understand the impact of long-term treatment with magnesium sulfate, as well as to clarify the neuroprotective role of this therapy.