Table 1 Patient characteristics according to duration of ritodrine hydrochloride infusion
Total | Duration of ritodrine hydrochloride infusion | P value | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
≤48 h | 3–6 days | 7–13 days | 14–27 days | ≥28 days | |||||||||
Number of patients | 134,959 | 23,178 | (17.2) | 21,550 | (16.0) | 21,911 | (16.2) | 29,556 | (21.9) | 38,764 | (28.7) | ||
Age in years, mean (SD) | < 20 | 2833 | 545 | (19.2) | 521 | (18.4) | 521 | (18.4) | 576 | (20.3) | 670 | (23.6) | < 0.001 |
20–24 | 12,399 | 2309 | (18.6) | 2213 | (17.8) | 2106 | (17.0) | 2755 | (22.2) | 3016 | (24.3) | ||
25–29 | 33,390 | 5657 | (16.9) | 5268 | (15.8) | 5451 | (16.3) | 7399 | (22.2) | 9615 | (28.8) | ||
30–34 | 46,216 | 7717 | (16.7) | 7209 | (15.6) | 7395 | (16.0) | 10,227 | (22.1) | 13,668 | (29.6) | ||
35–39 | 32,418 | 5522 | (17.0) | 5103 | (15.7) | 5223 | (16.1) | 6976 | (21.5) | 9594 | (29.6) | ||
≥40 | 7703 | 1428 | (18.5) | 1236 | (16.0) | 1215 | (15.8) | 1623 | (21.1) | 2201 | (28.6) | ||
BMI, kg/m2 | < 18.5 | 94,611 | 15,022 | (15.9) | 14,588 | (15.4) | 15,256 | (16.1) | 21,124 | (22.3) | 28,621 | (30.3) | < 0.001 |
18.5–24.9 | 6856 | 1182 | (17.2) | 983 | (14.3) | 1016 | (14.8) | 1366 | (19.9) | 2309 | (33.7) | ||
25.0–29.9 | 24,981 | 4938 | (19.8) | 4480 | (17.9) | 4230 | (16.9) | 5453 | (21.8) | 5880 | (23.5) | ||
≥30.0 | 5399 | 1306 | (24.2) | 1010 | (18.7) | 924 | (17.1) | 998 | (18.5) | 1161 | (21.5) | ||
Smoking | No | 109,253 | 18,309 | (16.8) | 17,172 | (15.7) | 17,815 | (16.3) | 24,195 | (22.1) | 31,762 | (29.1) | < 0.001 |
Yes | 12,636 | 2305 | (18.2) | 2258 | (17.9) | 2073 | (16.4) | 2641 | (20.9) | 3359 | (26.6) | ||
Multiple births | No | 120,943 | 21,562 | (17.8) | 20,230 | (16.7) | 20,137 | (16.6) | 25,989 | (21.5) | 33,025 | (27.3) | < 0.001 |
Yes | 14,016 | 1616 | (11.5) | 1320 | (9.4) | 1774 | (12.7) | 3567 | (25.4) | 5739 | (40.9) | ||
PROM | No | 130,527 | 21,338 | (16.3) | 20,527 | (15.7) | 21,351 | (16.4) | 29,054 | (22.3) | 38,257 | (29.3) | < 0.001 |
Yes | 4432 | 1840 | (41.5) | 1023 | (23.1) | 560 | (12.6) | 502 | (11.3) | 507 | (11.4) | ||
Placenta previa | No | 126,431 | 22,187 | (17.5) | 20,451 | (16.2) | 20,545 | (16.2) | 27,235 | (21.5) | 36,013 | (28.5) | < 0.001 |
Yes | 8528 | 991 | (11.6) | 1099 | (12.9) | 1366 | (16.0) | 2321 | (27.2) | 2751 | (32.3) | ||
Gestational age at admission in weeks, mean (SD) | 30 (3.7) | 31.1 | (3.9) | 30.7 | (4.0) | 31.1 | (3.7) | 30.7 | (3.1) | 27.9 | (2.9) | < 0.001 | |