Strengths and Limitations
This study was the first to establish nomogram for predicting PTB in
patients with a short cervix. We describe predictors of PTB and their
associated relationships. The key limitation of this study was that the
sample size was not large. This could have affected the power of the
effects observed. Although only 12 pregnancies was not
clinically-indicated preterm births, the primary outcome of the study is
PTB which could be classified into different subtypes according to
clinical presentation including spontaneous preterm and
clinically-indicated preterm births.