Benefits, harms, and costs
- 1“Imminent preterm birth” is defined as a high likelihood of birth due to 1 or both of the following conditions (II-2):
- •Active labour with ≥4cm of cervical dilation, with or without preterm pre-labour rupture of membranes.
- •Planned preterm birth for fetal or maternal indications.
- 1For women with imminent preterm birth (≤33 + 6 weeks), antenatal magnesium sulphate administration should be considered for fetal neuroprotection (I-A).
- 2Although there is controversy about upper gestational age, antenatal magnesium sulphate for fetal neuroprotection should be considered from viability to ≤33 + 6 weeks (II-1B).
- 3If antenatal magnesium sulphate has been started for fetal neuroprotection based on a clinical diagnosis of imminent preterm birth, tocolysis is no longer indicated and should be discontinued (III-A).
- 4Magnesium sulphate should be discontinued if delivery is no longer imminent or a maximum of 24hours of therapy has been administered (II-2B).
- 5For women with imminent preterm birth, antenatal magnesium sulphate for fetal neuroprotection should be administered as a 4-g intravenous loading dose, over 30 minutes, with or without a 1g per hour maintenance infusion until birth (II-2B).
- 6For planned preterm birth for fetal or maternal indications, magnesium sulphate should be started, ideally within 4hours before birth, as a 4-g intravenous loading dose, over 30 minutes (II-2B).
- 7There is insufficient evidence that a repeat course of antenatal magnesium sulphate for fetal neuroprotection should be administered (III-L).
- 8Delivery should not be delayed in order to administer antenatal magnesium sulphate for fetal neuroprotection if there are maternal and/or fetal indications for emergency delivery (III-E).
- 9When magnesium sulphate is given for fetal neuroprotection, maternity care providers should use existing protocols to monitor women who are receiving magnesium sulphate for preeclampsia/eclampsia (III-A).
- 10Indications for fetal heart rate monitoring in women receiving antenatal magnesium sulphate for neuroprotection should follow the fetal surveillance recommendations of the Society of Obstetricians and Gynaecologists of Canada 2007 Fetal Health Surveillance: Antepartum and Intrapartum Consensus Guideline (III-A).
- 11Decisions about neonatal resuscitation should not be influenced by whether or not the other received magnesium sulphate for fetal neuroprotection (II-I B).
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This document reflects emerging clinical and scientific advances on the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. Local institutions can dictate amendments to these opinions. They should be well documented if modified at the local level. None of these contents may be reproduced in any form without prior written permission of the publisher.
All people have the right and responsibility to make informed decisions about their care in partnership with their health care providers. In order to facilitate informed choice, patients should be provided with information and support that is evidence-based, culturally appropriate and tailored to their needs.
This guideline was written using language that places women at the centre of care. That said, the SOGC is committed to respecting the rights of all people - including transgender, gender non-binary, and intersex people - for whom the guideline may apply. We encourage healthcare providers to engage in respectful conversation with patients regarding their gender identity as a critical part of providing safe and appropriate care. The values, beliefs and individual needs of each patient and their family should be sought and the final decision about the care and treatment options chosen by the patient should be respected.