Table 1.
Baseline and MgSO4-related clinical characteristics of the study population
| Period 1 (n = 79) | Period 2 (n = 72) | Period 3 (n = 75) | p value | |
|---|---|---|---|---|
| Baseline characteristics | ||||
| Gestational age, weeks (min, max) | 24.0±0.9 (22+1, 25+6) | 24.2±0.1 (22+5, 25+6) | 23.9±0.9 (22+1, 25+6) | 0.201 |
| Birth weight, g (min, max) | 667±145 (320, 940) | 683±134 (300, 950) | 667±129 (380, 940) | 0.719 |
| Male, n (%) | 45 (57) | 39 (54) | 39 (52) | 0825 |
| Small for gestational age, n (%) | 13 (16) | 11 (15) | 13 (17) | 0.945 |
| Apgar score at 1 min | 4.3±1.6 | 4.4±1.4 | 4.3±1.7 | 0.957 |
| Apgar score at 5 min | 6.8±1.9 | 6.9±1.3 | 7.0±1.6 | 0.546 |
| Cesarean delivery, n (%) | 57 (72) | 55 (76) | 39 (52) | 0.003 |
| Antenatal steroid use, n (%) | 76 (94) | 66 (92) | 73 (97) | 0.325 |
| Preterm premature rupture of membranes, n (%) | 30 (38) | 22 (31) | 37 (49) | 0.063 |
| Histologic chorioamnionitis, n (%) | 50 (63) | 40 (56) | 57 (87) | 0.031 |
| Preeclampsia, n (%) | 5 (6) | 6 (8) | 4 (5) | 0.759 |
| Gestational diabetes, n (%) | 2 (3) | 1 (1) | 1 (1) | 0.816 |
|
| ||||
| Antenatal MgSO4 use, n (%) | ||||
| For any purpose | 19 (24) | 56 (78) | 16 (21) | |
| For neuroprotection | 1 (3) | 40 (56) | 0 (0) | <0.001 |
| For severe preeclampsia | 5 (6) | 6 (8) | 4 (5) | |
| For tocolysis | 13 (16) | 10 (14) | 12 (16) | |
|
| ||||
| Serum MgSO4 level of EPIs | ||||
| Initial level (<1 h), mg/dL | 2.6±1.3 | 2.8±0.9 | 2.3±0.6 | 0.021 |
| Peak level within the first week, mg/dL | 2.8±1.0 | 3.0±0.7 | 2.7±0.5 | <0.001 |
| Initial ionized calcium level, mmol/L | 1.26±0.17 | 1.28±0.14 | 1.25±0.15 | 0.408 |
| Total intake on day 1, mL/kg/day | 70±7 | 73±6 | 71±10 | 0.888 |
| Total intake on day 7, mL/kg/day | 110±12 | 109±18 | 113±13 | 0.932 |
|
| ||||
| Type of milk during the first month or until alive, n (%) | ||||
| Exclusive breastfeeding | 34 (43) | 37 (51) | 40 (53) | |
| Partial breastfeeding | 31 (39) | 23 (32) | 31 (41) | 0.231 |
| Formula milk | 8 (10) | 6 (8) | 2 (3) | |
| Nil per os | 6 (8) | 6 (8) | 2 (3) | |
MgSO4, magnesium sulfate; EPI, extremely premature infant.