Conclusions
This study demonstrates that gestational age of 1stshort cervix, and CL of 1st short cervix, as well as other factors are predictors of overall PTB < 37 weeks and PTB < 34 weeks among patients with a short cervix. In addition, we have established nomogram that can help obstetricians to identify patients at risk of PTB. A combination of this prediction model and transvaginal ultrasonography may be efficient for clinical screening of short cervix