he largest comparative study was Manesium Suate or Prevention of Eclampsia reported by the Magpie Trial Collaboration Group (2002). More than 10,000 women with severe preeclampsia from 33 countries were randomly allocated to treatment with magnesium sulfate or placebo. Women given magnesium had a 58-percent significantly lower risk of eclampsia than those given placebo. In follow-up data of infants born to these mothers given magnesium sulfate, child behavior at approximately 18 months did not difer in those exposed compared with those not exposed to magnesium sulfate (Smyth, 2009).
Who Should Be Given Magnesium Sulfate?
Magnesium will prevent proportionately more seizures in women with correspondingly worse disease. However, severity is diicult to quantiy, and thus deciding which individual woman might benefit most from neuroprophylaxis is diicult. The 2013 Task Force recommends that women with either eclampsia or severe preeclampsia should be given magnesium sul ate prophylaxis. Again, criteria that establish "severity" are not totally uniform (see Table 40-2). At the same time, however, the 2013 Task Force suggests that women with "mild" preeclampsia do not need magnesium sulfate neuroprophylaxis. The conundrum is whether or not to give neuroprophylaxis to any of these women with "nonsevere" gestational hypertension or preeclampsia (Alexander, 2006).
In most other countries, and principally following dissemination of the Magpie Trial Collaboration Group (2002) study results, magnesium sulfate is now recommended for women with severe preeclampsia. In some, however, debate continues concerning whether therapy should be reserved for women who have an eclamptic seizure. We believe that eclamptic seizures are dangerous (pp. 722 and 745). Maternal mortality rates of up to 5 percent have been reported even in recent studies. Moreover, perinatal mortality rates are substantially increased (Abd EI Aal, 2012; Knight, 2007; Ndaboine, 2012; Schutte, 2008; von Dadelszen, 2012). Finally, the possibility of adverse longterm neuropsychological and vision-related sequelae of eclampsia have raised additional concerns that eclamptic seizures are not "benign."
Because of the foregoing, there is uncertainty about which women with nonsevere gestational hypertension should be given magnesium sulfate neuroprophylaxis. An opportunity to address these questions was aforded by a change in our prophylaxis protocol at Parkland Hospital. Before this time, the risk of eclampsia without magnesium prophylaxis was approximately 1 in 100 for women with mild preeclampsia (Lucas, 1995). Up until 2000, all women with gestational hypertension were given magnesium prophylaxis intramuscularly. Mter 2000, we instituted a standardized protocol for intravenously administered magnesium sulfate (Alexander, 2006). At the same time, we
TABLE 40-15. Selective versus Universal Magnesium
Sulfate Prophylaxis: Parkland Hospital
Criteria to Define Severe Gestational
In a woman with new-onset proteinuric hypertension, at least one of the following criteria is required:
Systolic BP : 160 r diastolic BP : 110 mm Hg
Proteinuria :2+ by dipstick in a catheterized urine
Serum creatininen> 1n.1 mg/dL
Platelet count < 1OO,OOO/1L above upper limit of normal range
BP = blood pressure. Criteria based on those from [Jational High Blood Pressure Education Program Working Group, 2000; American (ollege of Obstetricians and Gynecologists, 2012; cited by Alexander, 2006.