BACKGROUND AND PURPOSE:

• Vigil-DeGracia et al. (BJOG 2018) examined whether initial load and maintenance of MgS04 for a minimum of 8 hours before delivery requires another 24 hours of MgS04 post-delivery to reduce postpartum eclampsia

METHODS:

• Randomized multicenter controlled trial (RCT)
  • MAG‐PIP (MAGnesium Postpartum In Preeclampsia) trial
  • Participants: Women with severe preeclampsia (severity criteria met >20 weeks gestation)
• All women received 4 g loading dose followed by 1 g per hour for 8 hours as maintenance dose before delivery, then randomized to receive either
  • MgS04 continued for 24 hours postpartum
  • MgS04 Discontinued after delivery
• Statistical analysis – calculated for a no-inferiority study
  • Using alpha error of 5% and power of 90%, the study required 511 women per group
• Primary outcome
  • Incidence of eclampsia in the first 24 hours postdelivery
• Secondary outcomes
  • Maternal death | Maternal complications (e.g., PPH, respiratory difficulty etc.) | Time to ambulation | Time to lactation

RESULTS:

• 1,113 women were randomized
  • 555 patients MgS04 group | 558 no MgS04
  • Maternal characteristics similar between groups

Primary Outcome

• There was no statistical difference in rate of eclampsia between groups
  • 0.18% in the MgS04 group vs 0.35% in the no MgS04 group
  • Relative Risk (RR) 0.7, 95% CI 0.1-3.3 (P=0.50)
  • 1 woman in the MgS04 group vs 2 women in the MgS04 group

Secondary Outcomes

• No difference detected for total maternal complications
  • RR 1.0, 95% CI 0.8-1.2 (P = 0.76)
  • No differences detected for specific complications
• Time to start ambulation was significantly shorter (6 hours) in the no MgS04 group
  • 18.1 ± 10.6 versus 11.8 ± 10.8 hours (P = 0.0001)
• Time to start lactation was shorter (7 hours) in the no MgS04 group
  • 24.1 ± 17.1 versus 17.1 ± 16.8 hours (P = 0.0001)

CONCLUSION:

• There is no benefit of continuing MgS04 administration postpartum to prevent eclampsia
  • Women in the no MgS04 group ambulated and started breastfeeding sooner
• 50% of patients in both groups received antihypertensives postpartum
  • Not well understood but may impact eclampsia rates
• Women with more complications were excluded, and these patients (e.g. with HELLP syndrome) should receive ongoing MgS04 postpartum
• The authors caution due to sample size limitation
  • Power calculation was based on a higher eclampsia rate (2%) than observed in the study in the control group (0.35%)

Learn More – Primary Sources:

Is there benefit to continue magnesium sulphate postpartum in women receiving magnesium sulphate before delivery? A randomised controlled study.

Related ObG Topics:

Eclampsia and Role of Magnesium Sulfate

Aspirin Treatment for Women at Risk for Preeclampsia – ACOG and USPSTF Recommendations  

Is Eclampsia in Pregnancy Linked with Greater Risk for Seizure Disorder?