What should you know about magnesium sulfate in preterm labour?

Preterm labour means labour begins before the baby is ready for a full-term birth. When early birth appears possible, a maternity or neonatal team may discuss magnesium sulfate as part of care intended to reduce the chance of neurological injury for the baby. It is not a medicine that stops labour, and it is separate from antenatal steroid injections, which help prepare the baby's lungs. Magnesium sulfate may cause warmth, flushing, nausea or sleepiness. Staff monitor you closely because the safest plan depends on your condition and how soon birth may occur.

Contact your maternity unit promptly if you have regular tightening, pelvic pressure, fluid leakage or bleeding before your expected birth date. In hospital, clinicians may assess contractions, the cervix, your observations and the baby's heart rate. Tell them about allergies, kidney problems, breathing symptoms and current medicines. Ask how magnesium sulfate fits with [Antenatal Steroid Injection](/treatments/pregnancy-and-birth-care/antenatal-corticosteroid-injection/) and whether transfer to a neonatal service is needed.

Call your maternity unit or emergency services immediately for suspected waters breaking, vaginal bleeding, painful regular contractions, reduced fetal movement, severe abdominal pain, difficulty breathing or a seizure. Do not wait for a routine appointment when these symptoms occur. If you are receiving magnesium sulfate, report increasing weakness, extreme sleepiness or breathing changes to staff at once.

Ask why magnesium sulfate is recommended, what benefit the team expects for the baby, how you will be monitored, whether labour can be delayed, and which neonatal services are available. You can also ask whether [Cervical Cerclage](/treatments/pregnancy-and-birth-care/cervical-cerclage/) is relevant to your history or current findings.