Procedures for fetal neuroprotection: use of magnesium sulfate

Abstract

Perinatal factors resulting from prematurity are the main agents responsible for high child morbidity and mortality worldwide 1 . Therefore, the impact of premature birth is currently one of the biggest obstetric challenges. Prematurity is classified as spontaneous or elective 2 . The spontaneous one is the result from spontaneous delivery labor in the strict sense of this term or from rupture of the membranes, and it occurs more frequently in multiple pregnancies. On the other hand, elective prematurity is a consequence of a medical indication due to maternal intercurrent events (hypertensive emergencies, diabetic decompensation or placental displacement, among others).Extreme prematurity is the most feared condition, which results from deliveries at gestational ages of less than 32 weeks. Because prematurity may perform an irreversible neurological damage to the child, it has the capacity to cause a wide spectrum of diseases and permanent conditions, with varying degrees of impairment with regard to both neurological and psychomotor development 3 . Although use of magnesium sulfate to provide prophylaxis against eclampsia and inhibit preterm delivery labor is a well-established therapeutic approach, its use with the aim of fetal neuroprotection has been addressed only in more recent studies. Magnesium promotes cerebral vasodilatation, thereby it reduces the production of cytokines and free radicals and the entry of calcium into the intracellular medium, which minimizes cell injury and consequent death and optimizes the cerebral blood flow 4 . In 1995, a case-control study reported that sulfation in cases of extreme prematurity was probably associated with fetal neuroprotection effects 5 . Following this, other analyses were conducted on its applicability within obstetrics as a prevention for neurological lesions in extremely premature infants.Since only some of the subsequent studies showed that magnesium sulfate had a neuroprotective effect 6,7 , while others reported that this effect might not be sustainable [8][9][10] , new randomized studies were developed.A systematic review from the Cochrane Collaboration produced a meta-analysis of five randomized clinical trials that assessed the effect of neuroprotection provided through using magnesium sulfate in cases of prematurity 11 . This review showed that its use significantly reduced the risk of cerebral palsy, but did not increase fetal, neonatal, infant (up to two years of age) or maternal mortality. The dose used in the different studies ranged on average from Editorial