What do you use magnesium sulfate for?

3 reasons in obstetr: 1) to stop contractions for 48 hours in order to get the fetus time to mature its lungs with steroids, in case of preterm labor <34 weeks. 2)to prevent severe cerebral palsy in the offspring of women with ruptured membranes and/or preterm labor <32 weeks. 3)to prevent seizures in women with preeclampsia (severe only?) at high-risk periods (e.g. Labor, first 24 hours postpartum).