Table 1.
Characteristics of the Maternofetal Dyad and the Delivery Attempt, Both for the Full Data Set and Stratified By Outcome
| Characteristic | All Patients (N=3798) |
Successful Instrumentals (n=3552) |
Unsuccessful Instrumentals (n=246) |
|---|---|---|---|
| Maternal age | 30.1 (19–40) | 30.1 (19–40) | 30.0 (18–40) |
| Maternal BMI | 25.0 (18–36) | 25.0 (18–36) | 25.2 (19–40) |
| Birth weight | 3487 (2610–4440) | 3460 (2600–4430) | 3709* (2945–4654) |
| Gestation | 39.9 (37–42) | 39.9 (37–42) | 40.1† (38–42) |
| Ethnicity | |||
| Caucasian | 3352 | 3131 | 221 |
| Southeast Asian | 210 | 197 | 13 |
| Black | 43 | 41 | 2 |
| Chinese | 59 | 58 | 1 |
| Other/Unknown | 134 | 125 | 9 |
| Parity | |||
| 0 | 2008 | 1879 | 130 |
| 1 | 1545 | 1438 | 105 |
| 2 | 198 | 189 | 8 |
| 3 | 29 | 27 | 3 |
| 4+ | 18 | 19 | 0 |
| Time Fully Dilated | 132.3 (12–282) | 128.8 (12–275) | 132.5* (32–327) |
| Rotation Required | |||
| Yes | 365 | 317 | 48* |
| No | 3433 | 3235 | 198 |
| Instrument Used | |||
| Forceps | 2212 | 2076 | 136 |
| Ventouse | 1572 | 1476 | 96 |
| Both | 14 | 0 | 14 |
| Epidural | |||
| Yes | 2338 | 2173 | 165* |
| No | 1146 | 1076 | 70 |
| Unknown | 314 | 303 | 11 |
| Accoucheur | |||
| Type 1 | 70 | 70 | 0 |
| Type 2 | 2760 | 2632 | 128* |
| Type 3 | 718 | 629 | 89 |
| Type 4 | 236 | 208 | 28 |
| Unknown | 14 | 13 | 1 |
Data are mean (95% confidence interval) or n. Numerical data are summarized by the mean and a coverage interval (in parentheses) spanning the 2.5–97.5 percentiles. Associations that meet the threshold for statistical significance (alpha-level = 0.05) are shown in boldface.
*
p<0.001.
†
p<0.01.