Medically-induced PTBsa | Spontaneous PTBsa | Term birthsb | p-valuec | |
---|---|---|---|---|
(N = 466) | (N = 930) | (N = 3281) | ||
Mean (SD) | ||||
Maternal age (years) | 29.5 (6.8) | 28.0 (6.6) | 27.8 (6.4) | <0.001 |
Gestational age at birth (weeks) | 33.7 (3.0) | 33.7 (3.4) | 39.5 (1.3) | <0.001 |
Prepregnancy BMI (kg/m2) | 27.1 (6.6) | 25.5 (6.0) | 25.8 (6.1) | <0.001 |
Birth weight (grams) | 1989 (734) | 2237 (716) | 3239 (563) | <0.001 |
N (%) | ||||
Prepregnancy BMI (kg/m2) | <0.001 | |||
<18.5 | 13 (2.8) | 54 (5.8) | 149 (4.5) | |
18.5-24.9 | 188 (40.3) | 444 (47.7) | 1613 (49.2) | |
25.0-29.9 | 136 (29.2) | 269 (28.9) | 915 (27.9) | |
≥ 30.0 | 129 (27.7) | 163 (17.5) | 604 (18.4) | |
Hypertensive disorders of pregnancy | <0.001 | |||
None | 179 (38.7) | 850 (92.1) | 3004 (92.2) | |
Chronic hypertension | 19 (4.1) | 27 (2.9) | 71 (2.2) | |
Mild preeclampsia | 60 (13.0) | 24 (2.6) | 123 (3.8) | |
Severe hypertensive disorders (severe pre-eclampsia, eclampsia, HELLP syndrome) | 205 (44.3) | 22 (2.4) | 61 (1.9) | |
Chorioamnionitis | <0.001 | |||
None | 125 (26.8) | 252 (27.1) | 1265 (38.6) | |
Subclinical chorioamnionitis | 117 (25.1) | 157 (16.9) | 578 (17.6) | |
Clinical chorioamnionitis | 35 (7.5) | 239 (25.7) | 302 (9.2) | |
Unknown | 189 (40.6) | 282 (30.3) | 1136 (34.6) | |
Glucose tolerance | <0.001 | |||
No | 401 (86.4) | 855 (92.3) | 3090 (94.5) | |
Gestational diabetes | 39 (8.4) | 46 (5.0) | 145 (4.4) | |
Diabetes mellitus before index pregnancy | 24 (5.2) | 25 (2.7) | 35 (1.1) | |
Gestational weight gain per 2009 IOM | <0.001 | |||
Inadequate | 50 (10.7) | 118 (12.7) | 479 (14.6) | |
Adequate | 38 (8.2) | 115 (12.4) | 635 (19.4) | |
Excessive | 148 (31.8) | 306 (32.9) | 853 (26.0) | |
Unknown | 230 (49.4) | 391 (42.0) | 1314 (40.0) | |
Married | 159 (34.2) | 250 (26.9) | 1183 (36.2) | <0.001 |
Household income | 0.13 | |||
< $30,000/yr | 213 (45.7) | 475 (51.1) | 1580 (48.2) | |
≥ $30,000/yr | 69 (14.8) | 100 (10.8) | 387 (11.8) | |
Unknown | 184 (39.5) | 355 (38.2) | 1314 (40.0) | |
Education | 0.02 | |||
< High school | 138 (29.6) | 310 (33.3) | 1100 (33.5) | |
High school | 176 (37.8) | 336 (36.1) | 1055 (32.2) | |
> High school | 152 (32.6) | 284 (30.5) | 1126 (34.3) | |
Maternal race/ethnicity | 0.003 | |||
White | 52 (11.2) | 130 (14.0) | 342 (10.4) | |
Black | 260 (55.8) | 482 (51.8) | 1646 (50.2) | |
Hispanic | 106 (22.7) | 213 (22.9) | 892 (27.2) | |
Other | 48 (10.3) | 105 (11.3) | 401 (12.2) | |
Maternal smoking 3 months before or during index pregnancy | 98 (21.0) | 275 (29.6) | 591(18.0) | <0.001 |
Maternal stress during pregnancy | <0.001 | |||
No stress | 144 (31.1) | 304 (33.1) | 1269 (38.9) | |
Average stress | 194 (41.9) | 396 (43.1) | 1385 (42.4) | |
Very stressful | 125 (27.0) | 218 (23.7) | 612 (18.7) | |
Any illicit drug use during pregnancy | 76 (16.5) | 218 (23.5) | 432 (13.2) | <0.001 |
Alcohol use during pregnancy | 30 (6.5) | 65 (7.0) | 211 (6.4) | 0.84 |
Parity | 0.02 | |||
Nulliparous | 207 (44.4) | 385 (41.4) | 1381 (42.1) | |
Primiparous | 119 (25.5) | 239 (25.7) | 977 (29.8) | |
Multiparous | 140 (30.0) | 306 (32.9) | 923 (28.1) | |
Cervical incompetence | 16 (3.4) | 64 (6.9) | 37 (1.1) | <0.001 |
Placenta previa | 22 (4.7) | 29 (3.1) | 32 (1.0) | <0.001 |
Preterm premature rupture of membranes | 0 (0.0) | 439 (47.2) | 0 (0.0) | N/A |
Mode of delivery | <0.001 | |||
Vaginal | 136 (29.2) | 695 (74.8) | 2302 (70.2) | |
Cesarean section | 330 (70.8) | 234 (25.2) | 977 (29.8) | |
Delivery type | N/A | |||
Medically-induced | 466 (100.0) | 0 (0.0) | 971 (29.6) | |
Spontaneous | 0 (0.0) | 930 (100.0) | 2310 (70.4) | |
PTB according to gestational age | N/A | N/A | ||
Early PTB (<34 weeks) | 189 (40.6) | 320 (34.4) | ||
Late PTB (34–36 weeks) | 277 (59.4) | 610 (65.6) | ||
Infant sex- female | 247 (53.0) | 447 (48.1) | 1656 (50.5) | 0.20 |