Table 1. Baseline Characteristics for Pregnant Individuals.
| Magnesium sulfate (n = 729)a | Placebo (n = 704)a | |
|---|---|---|
| Participant age, mean (SD), y | 30.5 (6.2) | 30.6 (6.9) |
| Parity | ||
| 0 | 359 (49.2) | 379 (53.8) |
| ≥1 | 370 (50.8) | 325 (46.2) |
| Race and ethnicityb | ||
| Aboriginal or Torres Strait Islander | 22 (3.0) | 24 (3.4) |
| Asian | 127 (17.4) | 110 (15.6) |
| Māori | 43 (5.9) | 39 (5.5) |
| Pacific | 30 (4.1) | 31 (4.4) |
| White | 486 (66.7) | 480 (68.2) |
| Otherc | 21 (2.9) | 20 (2.8) |
| Body mass index, median (IQR)d | 25.0 (22.1-30.1) | 25.3 (22.2-29.8) |
| Gestational age at entry, mean (SD), wk | 32.1 (1.1) | 32.1 (1.1) |
| 30-<32 | 323 (44.3) | 308 (43.8) |
| 32-<34 | 406 (55.7) | 396 (56.3) |
| Socioeconomic statuse | ||
| Most disadvantaged | 192 (26.3) | 185 (26.3) |
| Disadvantaged | 108 (14.8) | 116 (16.5) |
| Middle | 171 (23.5) | 137 (19.5) |
| Advantaged | 140 (19.2) | 123 (17.5) |
| Most advantaged | 118 (16.2) | 143 (20.3) |
| Infant sex, No./total (%)f | ||
| Female | 385/858 (44.9) | 349/821 (42.5) |
| Male | 473/858 (55.1) | 472/821 (57.5) |
| Twin pregnancy | 130 (17.8) | 120 (17.0) |
| Prior event | ||
| Preterm birth (<37 weeks’ gestation) | 149 (20.4) | 128 (18.2) |
| Perinatal death (≥20 weeks’ gestation) | 31 (4.3) | 30 (4.3) |
| Prenatal use of corticosteroids | 709 (97.3) | 682 (96.9) |
| Reason at risk for preterm birth | ||
| Preterm labor | 207 (28.4) | 182 (25.9) |
| Preterm and prelabor rupture of membranes | 206 (28.3) | 183 (26.0) |
| Fetal compromise | 129 (17.7) | 129 (18.3) |
| Preeclampsia | 65 (8.9) | 81 (11.5) |
| Antepartum hemorrhage | 72 (9.9) | 67 (9.5) |
| Unspecified | 50 (6.9) | 62 (8.8) |
a
Data are expressed as No. (%) unless otherwise indicated.
b
Race and ethnicity were self-reported by the pregnant individual at study entry.
c
Included African, Middle Eastern, and South American.
d
Calculated as weight in kilograms divided by height in meters squared.
e
Derived from the Australian Socio-Economic Indexes for Areas29 and the New Zealand Socioeconomic Deprivation Profile.30
f
The denominators (858 + 821) equal the 1679 infants who were included in the randomization of the pregnant individuals.