Table 2 Study outcomes, expected results and key indicators

1a. Perinatal composite outcome (Main perinatal outcome)

Reduction in the rate of the composite perinatal outcome among infants of women exposed to Mg⁺⁺ vs. placebo

Preterm birth < 37 weeks gestation, stillbirth > 20 weeks gestation, neonatal death < 28 days after birth, or SGA birthweight < 10 percentile

1b. Preterm birth (PTB) (Secondary objective)

Reduction in the rate of PTB among infants of women exposed to Mg⁺⁺ vs. placebo

Birth at gestational age < 37 weeks

1c. Stillbirth (Secondary objective)

Reduction in the rate of stillbirths among pregnant women exposed to Mg⁺⁺

Fetal loss after 20 weeks gestation, in the absence of a major congenital anomaly evident at birth

1d. Small for gestational age birthweight < 10th percentile (Secondary objective)

Reduction in the rate of SGA among infants of women exposed to Mg⁺⁺ vs. placebo

SGA detected by a birthweight < 10th percentile

1e. Neonatal death < 28 days after birth (Secondary objective)

Reduction in the rate of neonatal death SGA among infants of women exposed to Mg⁺⁺ vs. placebo

Neonatal death of a liveborn infant from the date of birth up to and including 27 days after birth, in the absence of a major congenital anomaly evident at birth

1f. Neonatal intensive care unit (NICU) admission (Secondary objective)

Reduction in the rate of NICU admission among infants of women exposed to Mg⁺⁺ vs. placebo

NICU admission < 28 days after birth

2a. Maternal composite outcome (Main maternal outcome)

Reduction in the rate of the composite maternal outcome among women exposed to Mg⁺⁺ vs. placebo

Preeclampsia or eclampsia < 37 weeks gestation, severe gestational hypertension < 37 weeks gestation, placental abruption in pregnancy, or maternal stroke or death during pregnancy or ≤ 7 days after delivery

2b. Preeclampsia and eclampsia < 37 weeks gestation (Secondary objective)

Reduction in rate of preterm preeclampsia or eclampsia among pregnant women exposed to Mg⁺⁺ vs. placebo

Increased blood pressure > 140/90 mm Hg associated with ≥ 2 proteinuria, and/or seizures, and/or the HELLP Syndrome, arising < 37 weeks gestation

2c. Severe non-proteinuric hypertension < 37 weeks gestation (Secondary objective)

Reduction in rate of preterm severe non-proteinuric hypertension among pregnant women exposed to Mg⁺⁺ vs. placebo

Increased systolic blood pressure > 160 mm Hg or diastolic blood pressure > 105 mm Hg, with ≤ 1+ proteinuria, arising < 37 weeks gestation

2d. Maternal stroke (Secondary objective)

Reduction in rate of maternal stroke among pregnant women exposed to Mg⁺⁺ vs. placebo

Abrupt onset of a focal neurological deficit in the distribution of a brain artery persisting more than 24 hours due to intracerebral hemorrhage or ischemic infarction, arising during pregnancy or ≤ 7 days after delivery

2d. Maternal intensive care unit (ICU) admission (Secondary objective)

Reduction in the rate of maternal ICU admission among women exposed to Mg⁺⁺ vs. placebo

Adult ICU admission during pregnancy or ≤ 7 days after delivery