For women with eclampsia, magnesium sulphate is better than phenytoin for preventing further seizures and other health problems for the women and their babies.
Between two and eight in every 100 pregnant women develop pre-eclampsia (toxaemia), which usually means they have high blood pressure and protein in the urine. A few women with pre-eclampsia will also have a seizure (fit), this is called eclampsia. Eclampsia is rare: in high-income countries two to three in every 10,000 pregnant women have eclampsia, and in low- and middle-income countries 16 to 69 in every 10,000 pregnant women. It is an important condition because women who have eclampsia have a high risk of being seriously ill and dying. Worldwide, more than half a million women die each year due to complications of pregnancy and childbirth, and 99% of these deaths are women in low- and middle-income countries. Overall, 15% of maternal deaths are associated with eclampsia.
The review of seven trials, involving 972 women, found that magnesium sulphate was substantially better than phenytoin in reducing the risk of maternal death and of having further seizures. It also appears safer for the baby. Other drugs (diazepam and lytic cocktail) have also been compared with magnesium sulphate for women with eclampsia in other reviews; magnesium sulphate was substantially better than these too.