Table 1. Maternal medical background and obstetric outcomes of participants according to systemic lupus erythematosus status.
| Total participants | SLE | General population | p-value | |
|---|---|---|---|---|
| Variable | (n = 88,017) | (n = 63) | (n = 87,954) | |
| Maternal medical background | ||||
| Maternal age (y), mean (SD) | 31.3 (4.9) | 31.8 (4.4) | 31.3 (4.9) | 0.456 |
| BMI before pregnancy, mean (SD) | 21.2 (3.3) | 20.4 (2.6) | 21.2 (3.3) | 0.035 |
| Nulliparous, % (n) | 30.9 (27,169) | 50.8 (32) | 30.9 (27,137) | 0.001 |
| Smoking during pregnancy, % (n) | 4.6 (4,074) | 1.6 (1) | 4.6 (4,073) | 0.250 |
| Obstetric outcomes | ||||
| Gestational age (weeks), mean (SD) | 38.8 (1.6) | 37.5 (2.9) | 38.8 (1.6) | 0.001 |
| Preterm birth (<37 weeks), % (n) | 4.6 (4,036) | 28.6 (18) | 4.6 (4,018) | <0.001 |
| Preterm birth (<34 weeks), % (n) | 0.9 (811) | 4.8 (3) | 0.9 (808) | 0.001 |
| Birthweight (g), mean (SD) | 3025 (415.7) | 2580 (541.2) | 3026 (415.4) | <0.001 |
| LBW (<2500 g), % (n) | 8.0 (7,032) | 38.1 (24) | 8.0 (7,008) | <0.001 |
| LBW (<1500 g), % (n) | 0.5 (467) | 3.2 (2) | 0.5 (465) | 0.004 |
| SGA, % (n) | 5.1 (4,351) | 14.3 (9) | 5.1 (4,342) | 0.001 |
| pPROM, % (n) | 1.1 (975) | 12.7 (8) | 1.1 (967) | <0.001 |
| GH, % (n) | 3.1 (2736) | 4.8 (3) | 3.1 (2,733) | 0.449 |
| Still birth, % (n) | 0.1 (117) | 0 (0) | 0.1 (117) | 0.772 |
Abbreviations: SD: standard deviation, BMI: body mass index, PTB: preterm births, LBW: low birthweight infants, SGA: small-for-gestational age infants, pPROM: preterm premature rupture of membranes, GH: gestational hypertension