34 w (n: 302) 35 w (n: 504) 36 w (n: 1061) Total (n: 1867) Total (n: 1867) P
Mean age 32.8 ± 5.8 32.3 ± 5.6 32.5 ± 5.6 1867 1867 NS+
Primiparity 117 (38.7%) 193 (38.2%) 419 (39.5%) 729 (39%) 729 (39%) NS*
Previous PTB 25 (8.3%) 48 (9.5%) 84 (7.9%) 157 (8.4%) 157 (8.4%) NS*
Race Caucasian African South East Asian Other 233 (77.1%) 41 (13.6%) 16 (5.3%) 12 (4%) 390 (77.4%) 61 (12.1%) 20 (4%) 33 (6.5%) 832 (78.4%) 122 (11.5%) 37 (3.5%) 70 (6.6%) 1455 (77.9%) 224 (12%) 73 (3.9%) 115 (6.2%) 1455 (77.9%) 224 (12%) 73 (3.9%) 115 (6.2%)
NS*
Low education (< 8 years) 101 (33.4%) 153 (30.4%) 294 (27.7%) 548 (29.3%) 548 (29.3%) NS*
BMI 22.5 (20.7-25.9) 22.5 (20.2-25.9) 23.4 (20.2-25.4) 1867 1867 NS§
Excessive Weight Gain (IOM) 124 (60.8%) 221 (62.6%) 434 (56%) 779 (58.8%) 779 (58.8%) NS*
Smoking habit Smoking Stopped in pregnancy Stopped prior to pregnancy No smoking 30 (10.%) 17 (6%) 8 (2.8%) 229 (80.6%) 54 (10.9%) 25 (5%) 16 (3.2%) 400 (80.9%) 89 (9%) 45 (4.5%) 45 (4.5%) 809 (82%) 173 (9.8%) 87 (4.9%) 69 (3.9%) 1438 (81.4%) 173 (9.8%) 87 (4.9%) 69 (3.9%) 1438 (81.4%)
NS*
Assisted reproductive technologies 21 (6.9%) 23 (4.5%) 41 (3.8%) 85 (4.5%) 85 (4.5%) 0.08*
Diabetes Pregestational diabetes Class A2 GDM Class A1 GDM No diabetes 8 (2.6%) 15 (5%) 26 (8.6%) 253 (83.8%) 13 (2.6%) 14 (2.8%) 28 (5.6%) 449 (89%) 14 (1.3%) 20 (1.9%) 90 (8.5%) 937 (88.3%) 35 (1.9%) 49 (2.6%) 144 (7.7%) 1639 (87.8%) 35 (1.9%) 49 (2.6%) 144 (7.7%) 1639 (87.8%)
0.01*
Hypertensive disorders Chronic Hypertension Chronic Hypertension superimposed Preeclampsia Gestational Hypertension Preeclampsia Normotensive 9 (3%) 0 16 (5.3%) 14 (4.6%) 263 (87.1%) 9 (1.8%) 0 30 (5.9%) 23 (4.6%) 442 (87.7%) 15 (1.4%) 0 74 (7%) 29 (2.7%) 943 (88.9%) 33 (1.8%) 0 120 (6.4%) 66 (3.5%) 1648 (88.3%) 33 (1.8%) 0 120 (6.4%) 66 (3.5%) 1648 (88.3%)
NS**
Vaginal bleeding (Abruption/Placenta previa) 29 (9.6%) 55 (10.9%) 60 (5.7%) 144 (7.7%) 144 (7.7%) <0.01*
Liver disorders 10 (3.3%) 14 (2.8%) 40 (3.8%) 64 (3.4%) 64 (3.4%) NS*
pPROM 133 (44%) 205 (40.7%) 505 (47.6%) 843 (45.1%) 843 (45.1%) 0.03*
Clinical chorioamnionitis 1 (0.3%9 2 (0.4%) 7 (0.7%) 10 (0.5%) 10 (0.5%) 0.7
Type of labor No labour
106 (35.1%)
176 (35%)
270 (25.5%)
552 (29.6%)
552 (29.6%)
< 0.01*
Induced labour 41 (13.6%) 99 (19.7%) 226 (21.3%) 366 (19.6%) 366 (19.6%)
Spontaneous labour 155 (51.3%) 228 (45.3%) 563 (53.2%) 946 (50.8%) 946 (50.8%)
Mode of delivery Vaginal delivery (spontaneous and operative)
157 (52%)
257 (51.1%)
642 (60.6%)
1056 (50.6%)
1056 (50.6%)
< 0.01*
Cesarean in labor 39 (12.9%) 70 (13.9%) 147 (13.9%) 256 (13.7%) 256 (13.7%)
Cesarean not in labor 106 (35.1%) 176 (35%) 270 (25.5%) 552 (29.7%) 552 (29.7%)
Antenatal corticosteroids No steroids
111(36.7%)
305 (60.5%)
817 (77%)
1233 (66%)
1233 (66%)
< 0.01*
1 course 178 (58.9%) 195 (38.7%) 232 (21.9%) 605 (32.4%) 605 (32.4%)
2 courses 13 (4.4%) 4 (0.8%) 12 (1.1%) 29 (1.6%) 29 (1.6%)
ASA prophylaxis 10 (3.3%) 11 (2.2%) 23 (2.2%) 44 (2.3%) 44 (2.3%) NS*
LMWH prophylaxis 3 (1%) 8 (1.6%) 13 (1.2%) 24 (1.3%) 24 (1.3%) NS**
Progesterone Prophylaxis 23 (7.6%) 26 (5.2) 31 (2.9%) 80 (4.3%) 80 (4.3%) < 0.01*
Non ressuring fetal monitoring (category III sec ACOG) 18 (6%) 32 (6.3%) 51 (4.8%) 51 (4.8%) 101 (5.4%) NS*
Growth restriction (IUGR) 41 (13.6%) 68 (13.5%) 88 (8.3%) 88 (8.3%) 197 (10.5%) 0.01*
Diagnosis of fetal anomaly None
295 (97.7%)
496 (98.4%)
1039 (97.9%)
1039 (97.9%)
1830 (98%)
0.7**
Cardiovascular 3 (1%) 0 6 (0.6%) 6 (0.6%) 9 (0.5%)
CNS 0 2 (0.4%) 3 (0.3%) 3 (0.3%) 5 (0.2%)
Gastrointestinal 1 (0.3%) 2 (0.4%) 3 (0.3%) 3 (0.3%) 6 (0.3%)
Genito-urinary 0 0 2 (0.2%) 2 (0.2%) 2 (0.1%)
Others 3 (1%) 4 (0.8%) 8 (0.7%) 8 (0.7%) 15 (0.9%)
Amniotic fluid Oligo/anidramnios Polidramnios Normal 18 (6%) 7 (2.3%) 277 (91.7%) 31 (6.1%) 8 (1.6%) 465 (92.3%) 52 (4.9%) 16 (1.5%) 993 (93.6%) 52 (4.9%) 16 (1.5%) 993 (93.6%) 101 (5.4%) 31 (1.7%) 1735 (92.9%)
0.7