Table 1.
Main characteristics of women included in study (n=1598). Values are numbers (percentages) unless stated otherwise
| Characteristics | Term birth (38-43 weeks) (n=830) | Moderate preterm birth (32-36 weeks) (n=607) | Very/extreme preterm birth (20-31 weeks) (n=161) | Absolute risk of preterm birth (20-36 weeks) (%) |
|---|---|---|---|---|
| Maternal age at delivery (years) | ||||
| <20 | 2 (0.2) | 1 (0.2) | 1 (0.6) | 9.5 |
| 20 to 24 | 47 (5.7) | 48 (7.9) | 15 (9) | 12.3 |
| 25 to 29 | 204 (24.6) | 161 (26.5) | 45 (28) | 9.6 |
| 30 to 34 | 356 (42.9) | 244 (40.2) | 59 (37) | 8.2 |
| 35 to 39 | 196 (23.6) | 137 (22.6) | 36 (22) | 8.5 |
| ≥40 | 25 (3.0) | 16 (2.6) | 5 (3) | 8.1 |
| Parity before index birth | ||||
| None | 423 (51.0) | 314 (51.7) | 87 (54) | 9.0 |
| 1 | 205 (24.7) | 154 (25.4) | 36 (22) | 8.9 |
| 2 | 100 (12.0) | 67 (11.0) | 25 (16) | 8.8 |
| ≥3 | 102 (12.3) | 72 (11.9) | 13 (8) | 8.0 |
| Worst diagnosis at colposcopy | ||||
| Normal/benign | 109 (13.1) | 68 (11.2) | 17 (11) | 7.6 |
| Low grade disease* | 233 (28.1) | 136 (22.4) | 34 (21) | 7.1 |
| High grade disease† | 480 (57.8) | 394 (64.9) | 110 (68) | 9.9 |
| Inadequate/unknown | 8 (1.0) | 9 (1.5) | 0 (0) | 10.6 |
| Most invasive procedure at colposcopy | ||||
| Punch biopsy | 274 (33.0) | 175 (28.8) | 35 (22) | 7.4 |
| LLETZ/loop/cone‡ | 556 (67.0) | 432 (71.2) | 126 (78) | 9.5 |
*Includes human papilloma virus, cervical intraepithelial neoplasia (CIN) grade 1, and low grade glandular CIN.
†Includes CIN grade 2 and 3, high grade glandular CIN, and ungraded CIN or glandular CIN.
‡Large loop excision of the transformation zone (LLETZ), loop excision, or cone excision.