TABLE 2.
Pooled estimates for cervical length in predicting spontaneous preterm birth in women with twin pregnancies
| Outcome | Cervical length cut-off (mm) | No of studies | Sample size | Sensitivity (%) (95% CI) | Specificity (%) (95% CI) | Positive Likelihood ratio (95% CI) | Negative Likelihood ratio (95% CI) |
|---|---|---|---|---|---|---|---|
| Asymptomatic women | |||||||
| Testing at 20-24 weeks’ gestation | |||||||
| Preterm birth <28 weeks | 20 | 3 23,27,33 | 591 | 35 (14-62) | 93 (91-95) | 5.2 (2.6-10.6) | 0.69 (0.49-1.01) |
| 25 | 327,33,39 | 637 | 64 (41-83) | 93 (91-95) | 9.6 (5.8-14.8) | 0.40 (0.23-0.68) | |
| 35 | 327,33,39 | 637 | 82 (60-95) | 66 (62-69) | 2.4 (1.9-3.0) | 0.28 (0.11-0.67) | |
| Preterm birth <32 weeks | 20 | 523,25,27,30,33 | 1955 | 39 (31-48) | 96 (95-97) | 10.1 (7.4-13.9) | 0.64 (0.55-0.73) |
| 25 | 618,22,25,27,30,33 | 2036 | 54 (45-62) | 91 (90-92) | 6.0 (4.8-7.4) | 0.51 (0.43-0.61) | |
| 30 | 422,25,27,30 | 1812 | 65 (56-74) | 78 (76-80) | 3.0 (2.5-3.5) | 0.45 (0.35-0.57) | |
| 35 | 522,25,27,30,33 | 1889 | 81 (73-87) | 58 (56-61) | 1.9 (1.7-2.2) | 0.33 (0.23-0.48) | |
| Preterm birth <34 weeks | 20 | 523,26,27,30,33 | 1760 | 29 (23-35) | 97 (96-98) | 9.0 (6.1-12.7) | 0.74 (0.68-0.80) |
| 25 | 618,22,27,30,31,33 | 1987 | 40 (38-46) | 93 (92-94) | 5.8 (4.5-7.2) | 0.64 (0.58-0.71) | |
| 30 | 522,25,27,30,31 | 2014 | 56 (50-62) | 81 (79-83) | 3.0 (2.6-3.4) | 0.55 (0.48-0.63) | |
| 35 | 622,24,27,30,31,33 | 1884 | 79 (74-84) | 60 (57-62) | 2.0 (1.8-2.2) | 0.35 (0.27-0.44) | |
| Preterm birth <37 weeks | 25 | 418,22,29,33 | 434 | 21 (15-27) | 95 (92-98) | 4.4 (2.4-8.2) | 0.83 (0.75-0.92) |
| 30 | 222,29 | 218 | 29 (18-43) | 91 (86-95) | 3.4 (1.6-6.7) | 0.78 (0.65-0.92) | |
| 35 | 222,33 | 134 | 56 (43-68) | 63 (50-74) | 1.5 (1.0-2.2) | 0.71 (0.51-0.98) | |
| Testing after 24 weeks’ gestation | |||||||
| Preterm birth <32 weeks | 25 | 318,25,33 | 511 | 65 (45-81) | 76 (72-79) | 2.7 (2.0-3.6) | 0.47 (0.29-0.76) |
| Preterm birth <34 weeks | 25 | 418,25,26,33 | 594 | 44 (34-53) | 81 (78-85) | 2.3 (1.8-3.1) | 0.70 (0.59-0.83) |
| Preterm birth <37 weeks | 25 | 218,33 | 276 | 43 (35-51) | 77 (68-84) | 1.8 (1.3-2.6) | 0.75 (0.63-0.89) |
| Women with symptoms of preterm labor | |||||||
| Preterm birth <34 weeks | 30 | 234,38 | 92 | 79 (62-91) | 32 (20-45) | 1.2 (0.9-1.7) | 0.67 (0.31-1.44) |
| Preterm birth <37 weeks | 25 | 234,35 | 131 | 49 (38-60) | 74 (59-87) | 1.9 (1.1-3.3) | 0.69 (0.52-0.90) |
| 30 | 334,36,38 | 118 | 76 (65-84) | 37 (19-58) | 1.2 (0.9-1.7) | 0.65 (0.29-1.31) | |
a
Study # 39 is an initial report of study # 30