**5. Neuroprotection: the use of magnesium sulfate**

Among the less-than-5th-percentile infants, 28-day neonatal mortality was 225 per 1000 livebirths for the intervention group and 232 per 1000 livebirths for the control group (relative risk [RR] 0·96, 95% CI 0·87–1·06, p = 0·65), and suspected maternal infection was reported in 236/2361 (10%) women in the intervention group and 133/2094 (6%) in the control group

**Table 4.** Correlation between complications of SPB and use of corticosteroids (Cochrane Review, 2017 [2]).

Among the whole population, 28-day neonatal mortality was 27·4 per 1000 livebirths for the intervention group and 23·9 per 1000 livebirths for the control group (RR 1·12, 1·02–1·22, p = 0·0127), and suspected maternal infection was reported in 1207/48219 (3%) women in the intervention group and 867/51523 (2%) in the control group (OR 1·45, 1·33–1·58, p < 0·0001).

(odds ratio [OR] 1·67, 1·33–2·09, p < 0·0001).

200 Multiple Pregnancy - New Challenges

In 1995, it was suggested that magnesium sulfate was a neuroprotector, decreasing the prevalence of cerebral palsy in very-low-birthweight newborns [55]. Since then, several studies have been conducted to elucidate this aspect.

Despite clinical trials have failed proving reduction of infant death, the use of antenatal magnesium sulfate for neuroprotection statistically diminished the risk of cerebral palsy in the survivors [56, 57]. Therefore, its use is recommended in cases of high risk of imminent preterm birth, in single and multiple pregnancies, in gestations <32nd week, and after viability [7, 34].

Many mechanisms were proposed to explain the neuroprotective effect of magnesium sulfate, but the exact one is actually unknown. Other questions about magnesium sulfate that are not yet clarified are best dose regimen, treatment duration, and risks or benefits of retreatment. An interesting point that were recently approached is that the exposure to magnesium proximal to delivery (<12 hours) seems to be related to more significant reduction of cerebral palsy when compared to the last infusion of this drug more than 12 hours before delivery [58].

**Author details**

**References**

Marcelo Santucci Franca1

UNIFESP, São Paulo, Brazil

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\*, Tatiana E. N. K. Hamamoto1

2 Institute of Tropical Medicine, University of São Paulo (USP), São Paulo, Brazil

1 Discipline of Fetal Medicine, Obstetrics Department, Federal University of São Paulo—

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In UNIFESP, this drug is administered intravenously, with a loading dose of 4 g in 20 minutes, followed by 1 g/h for up to 24 hours or until delivery [40]. Monitoring these pregnant women (by continuous evaluation of patellar reflex, respiratory frequency, urine output) is essential to prevent magnesium toxicity. Myasthenia gravis and myocardial compromise are contraindications for the use of magnesium sulfate, and adjusted dose should be used in patients with renal insufficiency [59].
