Table 1.
Demographics and clinical characteristics of the study cohorts.
| Cohorts | VMET | VMET2 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Demographics | sPTB | Term | Total | P value | iPTB | sPTB | Term | Total | P value |
| Subject, n | 29 (18%) | 131 (82%) | 160 | 3 (1%) | 41 (20%) | 161 (79%) | 205 | ||
| Sample, n | 79 | 376 | 455 | 9 | 105 | 459 | 573 | ||
| Mean maternal age, years ± SD (range) | 32.2 ± 6.4 (20–43) | 22.7 ± 7.0 (8.7–36.7) | 22.5 ± 7.0 (8.7–36.7) | p = 0.17 | 38.0 ± 3.1 (34.0–41.0) | 32.7 ± 5.9 (20.0–44.0) | 33.2 ± 4.7 (20–43) | 33.3 ± 4.9 (20–44) | p = 0.50 |
| Mean sample gestation, weeks (±SD range) | 21.8 ± 6.8 (11.7–34.3) | 33.0 ± 5.0 (19–49) | 32.9 ± 5.2 (19–49) | p = 0.15 | 23.4 ± 7.2 (15.3–34.5) | 21.5 ± 6.4 (12.2–32.6) | 22.4 ± 6.8 (11.0–35.6) | 22.3 ± 6.8 (10.5–36) | p = 0.12 |
| Mean BMI, kg/m2 (±SD, range) | 26.2 ± 4.4 (18–36) | 24.2 ± 4.4 (18–48) | 24.5 ± 4.5 (18–48) | p = 0.0002 | 28.9 ± 3.5 (24.0–32.0) | 25.5 ± 5.6 (20.0–46.1) | 25.3 ± 5.1 (18.1–39.9) | 25.3 ± 5.1 (18.1–46.1) | p = 0.19 |
| Ethnicity, n/N (%) | |||||||||
| Caucasian | 17/113 (15%) | 96/113 (85%) | 113/160 (71%) | p = 0.14 | 2/130 (2%) | 20/130 (15%) | 108/130 (73%) | 130/205 (63%) | p = 0.66 |
| Asian | 1/11 (9%) | 10/11 (91%) | 11/160 (7%) | 0/28 (0%) | 8/28 (29%) | 20/28 (71%) | 28/205 (14%) | ||
| Black | 11/35 (31%) | 24/35 (69%) | 35/160 (22%) | 1/35 (3%) | 10/35 (29%) | 24/35 (69%) | 35/205 (17%) | ||
| Others | 0/0 (0%) | 0/0 (0%) | 0/160 (0%) | 0/12 (0%) | 3/12 (25%) | 9/12 (75%) | 12/205 (6%) | ||
| Not recorded* | 0/1 (0%) | 1/1 (100%) | 1/160 (0%) | 0/0 (0%) | 0/0 (0%) | 0/0 (0%) | 0/205 (0%) | ||
| Gravida | |||||||||
| 0 | 2/50 (4%) | 48/50 (96%) | 50/160 (31%) | p = 0.01 | 0/1 (0%) | 1/1 (100%) | 0/1 (0%) | 1/205 (0%) | p = 0.21 |
| 1 | 8/34 (24%) | 26/34 (76%) | 34/160 (21%) | 0/45 (0%) | 5/45 (11%) | 40/45 (89%) | 45/205 (22%) | ||
| 2 | 5/26 (19%) | 21/26 (81%) | 26/160 (17%) | 1/59 (2%) | 15/59 (25%) | 43/59 (73%) | 59/205 (29%) | ||
| >3 | 14/50 (28%) | 36/50 (72%) | 50/160 (31%) | 2/100 (2%) | 20/100 (20%) | 78/100 (78%) | 100/205 (49%) | ||
| Previous mid trimester loss/PTB | |||||||||
| No | 7/93 (8%) | 86/93 (92%) | 93/160 (58%) | p = 0.00004 | 1/86 (1%) | 7/86 (8%) | 78/86 (91%) | 86/205 (42%) | p = 0.001 |
| Yes | 22/67 (33%) | 45/67 (67%) | 67/160 (42%) | 2/119 (2%) | 34/119 (29%) | 83/119 (70%) | 119/205 (58%) | ||
| Previous excisional cervical treatment | |||||||||
| No | 24/147 (16%) | 123/147 (84%) | 147/160 (92%) | p = 0.045 | 0/105 (0%) | 15/105 (14%) | 90/105 (86%) | 105/205 (51%) | p = 0.029 |
| Yes | 5/13 (38%) | 8/13 (62%) | 13/160 (8%) | 1/100 (1%) | 28/100 (28%) | 71/100 (71%) | 100//205 (49%) | ||
| Cervical cerclage material intervention | |||||||||
| Braided | 10/45 (22%) | 35/45 (78%) | 45/160 (28%) | p = 0.22 | 1/26 (4%) | 13/26 (50%) | 12/26 (46%) | 26/205 (13%) | p = 0.0007 |
| Monofilament | 7/23 (30%) | 16/23 (70%) | 23/160 (14%) | 0/30 (0%) | 8/30 (27%) | 22/30 (73%) | 30/205 (15%) | ||
| Abdominal | 0/0 (0%) | 0/0 (0%) | 0/160 (0%) | 0/2 (0%) | 0/2 (0%) | 2/2 (100%) | 2/205 (1%) | ||
| No intervention | 12/92 (13%) | 80/92 (87%) | 92/160 (58%) | 2/142 (1%) | 18/142 (13%) | 122/142 (86%) | 142/205 (69%) | ||
| Not recorded* | 0/0 (0%) | 0/0 (0%) | 0/160 (0%) | 0/5 (0%) | 2/5 (40%) | 3/5 (60%) | 5/205 (2%) | ||
sPTB spontaneous preterm birth, iPTB iatrogenic preterm birth. Comparisons of means between sPTB and Term group were done using two-sided Student’s t-tests for continuous covariates (maternal age, sample gestation and BMI), and two-sided Pearson’s chi-squared tests were used to compare the distribution of categorical variables (ethnicity, gravida, previous mid trimester loss/PTB, previous excisional cervical treatment, cervical cerclage material intervention).