| Characteristic | Mean (range)or n (%)† |
| Maternal age (years) | 28.1 (15.0–41.0) |
| Maternal race/ethnicity | |
| White non-Hispanic | 33 (33) |
| Hispanic | 54 (54) |
| African American | 8 (8) |
| Asian/Pacific Islander | 5 (5) |
| Other | 1 (1) |
| Parity: primiparous | 42 (42) |
| Delivery type | |
| Vaginal | 74 (73) |
| Normal | 64 (63) |
| Forceps-assisted | 10 (10) |
| Caesarean section | 26 (26) |
| Elective | 15 (15) |
| Failure to progress | 8 (8) |
| Emergency | 3 (3) |
| Minutes pushing 2nd stage labour‡ | |
| 0–5 | 22 (26) |
| 6–30 | 22 (26) |
| 31–60 | 17 (20) |
| 61–270 | 24 (28) |
| Baby active | 99 (98) |
| Baby “stuck” 3rd trimester | 36 (36) |
| Number of weeks baby stuck | |
| 0 | 69 (68) |
| 1–6 | 9 (9) |
| 7–12 | 19 (19) |
| >12 | 4 (4) |
| Birth trauma | 10 (10) |
| Lie | |
| Vertex | 92 (91) |
| Breech | 3 (3) |
| Transverse | 1 (1) |
| Other | 4 (4) |
| Gestational age at delivery (weeks) | 39.6 (36.4–42.1) |
*Includes one twin gestation counted as one pregnancy.
†Missing value for one subject each for delivery type and lie; all percentages calculated using total size of 101 as denominator.
‡Excluding elective caesarean section and one missing value for length of 2nd stage labour.