Table 2.
Crude Rates of Preterm Birth by Ultrasound-Indicated Cerclage Group
| Cervical Length | Preterm Birth <35 wks | Preterm Birth <24 wks | |||
|---|---|---|---|---|---|
| Cerclage | No Cerclage | Cerclage | No Cerclage | ||
| <25mm | 45/142 (32%) | 67/159 (42%) | 8/142 (6%) | 22/159 (14%) | |
| <24mm | 36/117 (31%) | 55/121 (45%) | 8/117 (7%) | 19/121 (16%) | |
| <23mm | 34/100 (34%) | 48/93 (52%) | 8/100 (8%) | 17/93 (18%) | |
| <22mm | 29/83 (35%) | 44/81 (54%) | 6/83 (7%) | 14/81 (17%) | |
| <21mm | 25/71 (35%) | 38/67 (57%) | 6/71 (8%) | 12/67 (18%) | |
| <20mm | 24/61 (39%) | 37/58 (64%) | 6/61 (10%) | 12/58 (21%) | |
| <19mm | 22/50 (44%) | 35/53 (66%) | 6/50 (12%) | 12/53 (23%) | |
| <18mm | 20/46 (43%) | 29/42 (69%) | 6/46 (13%) | 11/42 (26%) | |
| <17mm | 17/42 (40%) | 26/37 (70%) | 5/42 (12%) | 11/37 (30%) | |
| <16mm | 16/39 (41%) | 20/29 (69%) | 5/39 (13%) | 9/29 (31%) | |
| <15mm | 13/36 (36%) | 20/28 (71%) | 5/36 (14%) | 9/28 (32%) | |
| <14mm | 12/30 (40%) | 18/26 (69%) | 5/30 (17%) | 8/26 (31%) | |
| <13mm | 12/29 (41%) | 16/23 (70%) | 5/29 (17%) | 7/23 (30%) | |
| <12mm | 11/23 (48%) | 16/20 (80%) | 4/23 (17%) | 7/20 (35%) | |
| <11mm | 8/17 (47%) | 14/16 (88%) | 4/17 (24%) | 5/16 (31%) | |
| <10mm | 8/16 (50%) | 13/14 (93%) | 4/16 (25%) | 5/14 (36%) | |