The use of intravenous magnesium in non-preeclamptic pregnant women: fetal/neonatal neuroprotection.

PURPOSE: To review the effect of intravenous magnesium in obstetrics on fetal/neonatal neuroprotection. METHODS: A systematic review of published studies. RESULTS: Five randomized trials and 4 meta-analyses have shown a significant 32% reduction of cerebral palsy when administering magnesium sulfate in case of preterm delivery. The pathophysiologic mechanism is not fully unraveled: modulation of the inflammatory process, both in the mother and the fetus, and downregulation of neuronal stimulation seem to be involved. After long-term high-dose intravenous administration of magnesium, maternal and neonatal adverse effects such as maternal and neonatal hypotonia and osteoporosis and specific fetal/neonatal cerebral lesions have been described. In case of administration for less than 48 h at 1 g/h and a loading dose of 4 g, these toxic amounts are not achieved. American, Canadian and Australian guidelines recommend the use of intravenous magnesium in any threatening delivery at less than 32 weeks. The "number needed to treat" to avoid 1 cerebral palsy is between 15 and 35. CONCLUSIONS: Intravenous magnesium significantly reduces the risk for cerebral palsy in preterm birth. Open questions remain the optimal dosing schedule, whether or not repeating when delivery has been successfully postponed and a new episode of preterm labor occurs. Some concern has been raised on a too optimistic value for random error which might have led to over-optimistic conclusions in classic meta-analysis. Randomized trials comparing different doses and individual patient data meta-analysis might resolve these issues.

Population Pharmacokinetics of Amoxicillin in Term Neonates Undergoing Moderate Hypothermia.

The pharmacokinetics (PK) of amoxicillin in asphyxiated newborns undergoing moderate hypothermia were quantified using prospective data (N = 125). The population PK was described by a 2-compartment model with a priori birthweight (BW) based allometric scaling. Significant correlations were observed between clearance (Cl) and postnatal age (PNA), gestational age (GA), body temperature (TEMP), and urine output (UO). For a typical patient with GA 40 weeks, BW 3,000 g, 2 days PNA (i.e., TEMP 33.5°C), and normal UO, Cl was 0.26 L/h (interindividual variability (IIV) 41.9%) and volume of distribution of the central compartment was 0.34 L/kg (IIV of 114.6%). For this patient, Cl increased to 0.41 L/h at PNA 5 days and TEMP 37.0°C. The respective contributions of both covariates were 23% and 27%. Based on Monte Carlo simulations we recommend 50 and 75 mg/kg/24h amoxicillin in three doses for patients with GA 36-37 and 38-42 weeks, respectively.

Perinatal cortical infarction within middle cerebral artery trunks.

AIM: To define neonatal pial middle cerebral artery infarction. METHODS: A retrospective study was made of neonates in whom focal arterial infarction had been detected ultrasonographically. A detailed study was made of cortical middle cerebral artery infarction subtypes. RESULTS: Forty infarctions, with the exception of those in a posterior cerebral artery, were detected ultrasonographically over a period of 10 years. Most were confirmed by computed tomography or magnetic resonance imaging. Factor V Leiden heterozygosity was documented in three. The onset was probably antepartum in three, and associated with fetal distress before labour in one. There were 19 cases of cortical middle cerebral artery stroke. The truncal type (n=13) was more common than complete (n = 5) middle cerebral artery infarction. Of six infarcts in the anterior trunk, four were in term infants and five affected the right hemisphere. Clinical seizures were part of the anterior truncal presentation in three. One of these infants, with involvement of the primary motor area, developed a severe motor hemisyndrome. The Bayley Mental Developmental Index was above 80 in all of three infants tested with anterior truncal infarction. Of seven patients with posterior truncal infarction, six were at or near term. Six of these lesions were left sided. Clinical seizures were observed in three. A mild motor hemisyndrome developed in at least three of these infants due to involvement of parieto-temporal non-primary cortex. CONCLUSIONS: Inability to differentiate between truncal and complete middle cerebral artery stroke is one of the explanations for the reported different outcomes. Severe motor hemisyndrome can be predicted from neonatal ultrasonography on the basis of primary motor cortex involvement. Clinical seizures were recognised in less than half of the patients with truncal infarction; left sided presentation was present in the posterior, but not the anterior truncal type of infarction. Asphyxia is a rare cause of focal arterial infarction.

Neonatal infarction within basal cerebral vein territory.

In this report, an unusual intracranial haemorrhage in a term male infant born to a mother with diabetes is explained on the basis of occlusion of both basal veins of Rosenthal. This diagnosis relies on anatomical location and iconographic aspect of the clots. Evidence that this vessel is occluded cannot be ascertained from ultrasound or MR angiographic techniques in the neonatal period. The basal vein has not been implicated in previous reports of neonatal brain haemorrhage.