Table 1.
Demographic and pregnancy characteristics of women admitted in spontaneous late preterm labor, stratified by timing of birth (n = 732)
| Characteristic/risk factor | Term birth (n = 301) | Late preterm birth (n = 431) | p-Value |
|---|---|---|---|
| Maternal age | 26.1 ± 5.5 | 26.4 ± 5.7 | 0.49 |
| Maternal race | 0.77 | ||
| Black or African American | 82 (27.2) | 110 (25.5) | |
| White | 166 (55.1) | 236 (54.8) | |
| Asian | 8 (2.7) | 17 (3.9) | |
| Other, unknown, or more than one race | 45 (15.0) | 68 (15.8) | |
| Nulliparity | 49 (16.3) | 113 (26.2) | <0.01 |
| Prepregnancy BMI (kg/m2) | 24.6 (21.6–28.3) | 24.1 (21.2–28.6) | 0.29 |
| Prior preterm birtha | 91/239 (38.1) | 99/283 (35.0) | 0.47 |
| Smoking any time during pregnancy | 41 (13.6) | 64 (14.9) | 0.64 |
| Use of “street drugs” any time during pregnancy | 15 (5.0) | 14 (3.3) | 0.24 |
| Alcohol use at any time during pregnancy | 9 (3.0) | 17 (3.9) | 0.50 |
| Abruption or significant bleeding during pregnancy | 8 (2.7) | 17 (3.9) | 0.35 |
| Any infections diagnosed this pregnancyb | 111 (36.9) | 128 (29.7) | 0.04 |
| Gestational age at randomization (weeks) | 35.5 ± 0.8 | 35.4 ± 0.8 | 0.09 |
| Contractions per hour at screening | 12 (8–16) | 12 (9–15) | 0.44 |
| Cervical dilation at randomization (cm) | 3 (3–4) | 4 (3–4.5) | <0.01 |
| Cervical effacement (%) at randomization | 60 (50–75) | 75 (50–90) | <0.01 |
| Fetal malpresentation | 1 (0.3) | 9 (2.1) | 0.05 |
| Mother’s length of hospital stay at delivery (days) | 2 (2–3) | 3 (2–3) | <0.01 |
Abbreviation: BMI, body mass index.
Note: Data are presented as n (%), mean ± standard deviation, or median (interquartile range), unless otherwise specified.
a
Previous delivery < 37 weeks’ gestation among multiparous women with gestational age data available.
b
Includes chlamydia, gonorrhea, syphilis, trichomonas, bacterial vaginosis, herpes, GBS urinary tract infection, rubella, hepatitis B, HIV, pyelonephritis, urinary tract infection, pneumonia, or cholecystitis.