Table 1a.
Maternal demographic, obstetric, and neonatal characteristics by timing of amniotomy among term, nulliparous labor inductions in the ARRIVE trial (2014-2017)
| Before oxytocin | 0 to <2 hours | 2 to <4 hours | ||||
|---|---|---|---|---|---|---|
| AROM n=333 |
No AROM n=2521 |
AROM n=279 |
No AROM n=2156 |
AROM n=444 |
No AROM n=1603 |
|
| Maternal demographic characteristics | ||||||
| Maternal age (years) | 25.6 ± 5.4 | 24.4 ± 5.1 | 25.7 ± 5.4 | 24.3 ± 5.1 | 25.1 ± 5.3 | 24.1 ± 5.0 |
| BMI (kg/m2) | 26.8 ± 6.9 | 27.3 ± 6.7 | 26.5 ± 5.8 | 27.4 ± 6.8 | 26.7 ± 6.7 | 27.7 ± 6.8 |
| Race/ethnicity | ||||||
| Non-Hispanic Black | 49 (14.7) | 623 (24.7) | 36 (12.9) | 570 (26.4) | 90 (20.3) | 456 (28.4) |
| Non-Hispanic White | 157 (47.1) | 1110 (44.0) | 181 (64.9) | 896 (41.6) | 231 (52.0) | 620 (38.7) |
| Other | 29 (8.7) | 112 (4.4) | 15 (5.4) | 93 (4.3) | 20 (4.5) | 68 (4.2) |
| Hispanic | 98 (29.4) | 676 (26.8) | 47 (16.8) | 597 (27.7) | 103 (23.2) | 459 (28.6) |
| Private insurance | 167 (50.2) | 1102 (43.7) | 183 (65.6) | 875 (40.6) | 230 (51.8) | 603 (37.6) |
| Married | 222 (66.7) | 1457 (57.8) | 197 (70.6) | 1212 (56.2) | 287 (64.6) | 869 (54.2) |
| Tobacco use | 13 (3.9) | 230 (9.1) | 17 (6.1) | 203 (9.4) | 36 (8.1) | 157 (9.8) |
| Obstetric characteristics | ||||||
| Gestational hypertension or preeclampsia | 35 (10.5) | 399 (15.8) | 35 (12.5) | 354 (16.4) | 56 (12.6) | 275 (17.2) |
| Gestational age at delivery (weeks) | 39.7 ± 0.7 | 39.7 ± 0.7 | 39.7 ± 0.7 | 39.7 ± 0.7 | 39.7 ± 0.7 | 39.7 ± 0.7 |
| Indication for induction | ||||||
| Elective | 224 (67.3) | 1776 (70.4) | 203 (72.8) | 1504 (69.8) | 301 (67.8) | 1133 (70.7) |
| Postdates | 54 (16.2) | 333 (13.2) | 35 (12.5) | 288 (13.4) | 69 (15.5) | 204 (12.7) |
| Fetal* | 29 (8.7) | 193 (7.7) | 17 (6.1) | 174 (8.1) | 37 (8.3) | 123 (7.7) |
| Maternal† | 26 (7.8) | 219 (8.7) | 24 (8.6) | 190 (8.8) | 37 (8.3) | 143 (8.9) |
| Modified Bishop score on admission | 4 (3–5) | 5 (3–6) | 5 (4–7) | 4 (3–6) | 5 (4–6) | 4 (3–5) |
| Cervical dilation on admission (cm) | 1 (1–2) | 1 (1–2) | 1 (1–2.5) | 1 (1–2) | 1 (1–2) | 1 (0.5–2) |
| Foley balloon for cervical ripening | 150 (45.0) | 1433 (56.8) | 121 (43.4) | 1270 (58.9) | 215 (48.4) | 1001 (62.4) |
| Prostaglandins for cervical ripening | 240 (72.1) | 1083 (43.0) | 146 (52.3) | 874 (40.5) | 188 (42.3) | 632 (39.4) |
| Hours from start of oxytocin to membrane rupture | −2.6 ± 3.0 | 6.9 ± 6.3 | 1.1 ± 0.6 | 7.9 ± 6.3 | 3.0 ± 0.6 | 9.6 ± 6.5 |
| Epidural anesthesia | 328 (98.5) | 2403 (95.3) | 272 (97.5) | 2049 (95.0) | 420 (94.6) | 1534 (95.1) |
| Neonatal characteristics | ||||||
| Male neonate | 154 (46.2) | 1253 (49.7) | 147 (52.7) | 1066 (49.4) | 221 (49.8) | 790 (49.3) |
| Birthweight (grams) | 3356 ± 408 | 3378 ± 398 | 3394 ± 407 | 3375 ± 397 | 3382 ± 411 | 3378 ± 394 |
Data presented as n (%), mean +/− standard deviation, or median (IQR).
Note: Bolded values represent statistical significance defined as p<0.05.
*
Fetal indications include intrauterine growth restriction, oligohydramnios, non-reassuring fetal status, and macrosomia.
†
Maternal indications include abruption, gestational hypertension or preeclampsia, and chorioamnionitis.
Number of missing values: BMI (n=16), insurance (n=1), modified Bishop score (n=211), cervical dilation on admission (n=147).