Table 1.
Baseline characteristics by delivery route
| Characteristic, n (%) or mean ± SD |
Delivery route | P-value CCD vs. VD* |
P-value LTCD vs. VD* |
P-value LVCD vs. VD* |
P-value CCD vs. LTCD* |
P-value CCD vs. LVCD* |
P-value LTCD vs. LVCD* |
|||
|---|---|---|---|---|---|---|---|---|---|---|
| Classical cesarean (CCD) n=272 |
Low transverse cesarean (LTCD) n=904 |
Low vertical cesarean (LVCD) n=29 |
Vaginal (VD) n=1454 |
|||||||
| Age, y | 28.4±6.7 | 28.0±6.5 | 28.4±6.8 | 26.5±6.5 | <.001 | <.001 | .13 | .45 | .90 | .73 |
| Race/ethnicity | .001 | .01 | .27 | <.001 | .18 | .41 | ||||
| Non-Hispanic white | 71 (26.1) | 394 (43.6) | 11 (37.9) | 559 (38.5) | ||||||
| Non-Hispanic black | 122 (44.9) | 268 (29.7) | 8 (27.6) | 522 (35.9) | ||||||
| Non-Hispanic other | 25 (9.2) | 75 (8.3) | 5 (17.2) | 111 (7.6) | ||||||
| Hispanic | 54 (19.9) | 167 (18.5) | 5 (17.2) | 262 (18.0) | ||||||
| Private insurance | 83 (30.6) | 363 (40.4) | 10 (34.5) | 486 (33.7) | .32 | .001 | .93 | .004 | .67 | .52 |
| Obstetric history | <.001 | <.001 | <.001 | .02 | .43 | .51 | ||||
| Nulliparous | 100 (36.8) | 411 (45.5) | 11 (39.3) | 682 (46.9) | ||||||
| Prior vaginal delivery only | 89 (32.7) | 229 (25.3) | 6 (21.4) | 671 (46.2) | ||||||
| Prior cesarean | 83 (30.5) | 264 (29.2) | 11 (39.3) | 100 (6.9) | ||||||
| Diabetes | .64 | <.001 | .03 | .14 | .03 | .04 | ||||
| None | 246 (90.4) | 778 (86.3) | 22 (75.9) | 1302 (89.9) | ||||||
| Pregestational | 10 (3.7) | 59 (6.5) | 1 (3.5) | 43 (3.0) | ||||||
| Gestational | 16 (5.9) | 65 (7.2) | 6 (20.7) | 103 (7.1) | ||||||
| Hypertension† | 135 (49.6) | 501 (55.4) | 16 (55.2) | 313 (21.6) | <.001 | <.001 | <.001 | .09 | .57 | .98 |
| Body mass index, kg/m2 | 33.5±9.3 | 32.1±7.4 | 34.6±8.4 | 29.8±7.2 | <.001 | <.001 | .001 | .11 | .35 | .10 |
| Smoked during pregnancy | 48 (17.7) | 147 (16.3) | 5 (17.2) | 288 (19.9) | .40 | .03 | .73 | .59 | .96 | .80 |
| PPROM | 82 (30.2) | 252 (27.9) | 7 (24.1) | 709 (48.8) | <.001 | <.001 | .009 | .47 | .50 | .66 |
| Preterm labor | 115 (42.3) | 336 (37.2) | 10 (34.5) | 1137 (78.2) | <.001 | <.001 | <.001 | .13 | .42 | .77 |
| Presentation at delivery | <.001 | <.001 | <.001 | <.001 | .76 | .09 | ||||
| Vertex | 94 (34.6) | 545 (60.3) | 12 (41.4) | 1411 (97.0) | ||||||
| Breech | 155 (57.0) | 333 (36.8) | 15 (51.7) | 42 (2.9) | ||||||
| Non-breech malpresentation | 23 (8.5) | 26 (2.9) | 2 (6.9) | 1 (0.1) | ||||||
| Gestational age at delivery, weeks | 27.8±2.8 | 30.8±2.5 | 29.0±2.8 | 30.7±3.0 | <.001 | .30 | .002 | <.001 | .02 | <.001 |
| Birthweight, grams | 1007.2±439.2 | 1517.8±564.5 | 1171.9±516.8 | 1634.6±580.5 | <.001 | <.001 | <.001 | <.001 | .05 | <.001 |
| Size for gestational age‡ | <.001 | <.001 | <.001 | .34 | .26 | .12 | ||||
| Small | 49 (18.0) | 130 (14.4) | 7 (24.1) | 70 (4.8) | ||||||
| Appropriate | 220 (80.9) | 763 (84.4) | 21 (72.4) | 1365 (93.9) | ||||||
| Large | 3 (1.1) | 11 (1.2) | 1 (3.5) | 18 (1.2) | ||||||
*
based on the chi-square or Fisher’s exact test for categorical variables and the Wilcoxon rank-sum test for continuous variables
†
includes chronic, gestational or preeclampsia
‡
estimated per the methods of Alexander et al (Alexander GR, Kogan MD, Himes JH. 1994–1996 U.S. singleton birth weight percentiles for gestational age by race, Hispanic origin, and gender. Matern Child Health J. 1999;3(4):225-31.) using neonatal gestational age at delivery, birthweight and sex and maternal race/ethnicity; small defined as < 10th percentile for sex and race/ethnicity; appropriate defined as 10th–90th percentile for sex and race/ethnicity; large defined as > 90th percentile for sex and race/ethnicity