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. Author manuscript; available in PMC: 2016 Dec 1.
Published in final edited form as: Am J Obstet Gynecol. 2015 Jun 10;213(6):789–801. doi: 10.1016/j.ajog.2015.06.015

TABLE 3.

Comparison of the predictive accuracy for preterm birth of cervical length at first and/or last measurement and change in cervical length over time in individual studies using the Youden index

Study
Outcome:
preterm
birth
Cervical length at initial measurement Cervical length at final measurement Change in cervical length over time
Cut-off value, (GA
at testing, wks)
Youden
index
P valuea Cut-off value, (GA
at testing, wks)
Youden
index
P valuea Abnormal test result Youden
index
Singleton gestation
Iams,4 1996 <35 wk 25 mm (24) 0.295 0.049 25 mm (28) 0.362 0.008 Any decrease in CL 0.165
<35 wk 25 mm (24) 0.295 0.44 25 mm (28) 0.362 0.12 Shortening of CL ≥6 mm 0.241
Arabin,48 2006 <36 wk Unreported (15–19) NC NA 25 mm (20–24) 0.080 0.66 Shortening of CL >10 mm 0.140
Dilek,50 2007 <37 wk 35.3 mm (16) 0.200 0.02 34.3 mm (24) 0.657 0.56 Shortening of CL ≥6.6 mm 0.556
Twin gestation
Bergelin,45 2003 <34 wk Unreported (24) NC NA 25 mm (28) 0.129 0.56 Shortening of CL ≥20% 0.314
Gibson,46 2004 <35 wk 25 mm (18) 0.128 0.87 25 mm (28) 0.042 0.43 Shortening of CL ≥2.5 mm/week 0.151
Arabin,48 2006 <36 wk Unreported (15–19) NC NA 20 mm (20–24) 0.080 0.06 Shortening of CL >10 mm 0.285
Fox,51 2010 <32 wk Unreported (18–24) NC NA 25 mm (20–25) 0.300 0.55 Shortening of CL ≥20% 0.427
<34 wk Unreported (18–24) NC NA 25 mm (20–25) 0.250 0.90 Shortening of CL ≥20% 0.231
Hofmeister,52
2010
<32 wk 5th percentile (18–21) 0.264 0.02 5th percentile (22–25) 0.478 0.35 Shortening of CL >2 mm/week 0.631
<34 wk 5th percentile (18–21 ) 0.206 0.04 5th percentile (22–25) 0.344 0.36 Shortening of CL >2 mm/week 0.470
Oh,54 2012 <32 wk Unreported (20–24) NC NA 30 mm (24–29) 0.503 0.98 Shortening of CL ≥13% 0.507
<34 wk Unreported (20–24) NC NA 30 mm (24–29) 0.482 0.50 Shortening of CL ≥13% 0.350
Khalil,55 2013 <32 wk Unreported (20–23) NC NA 25 mm (23–28) 0.367 0.28 Shortening of CL ≥25% 0.503
<34 wk Unreported (20–23) NC NA 25 mm (23–28) 0.317 0.03 Shortening of CL ≥25% 0.510
Levêque,56 2015 <34 wk 35 mm (22) 0.093 0.71 25 mm (27) 0.412 0.23 Shortening of CL ≥20% 0.170

CL, cervical length; GA, gestational age; NA, not applicable; NC, not calculable

a

For the difference with Youden index of change in cervical length over time