Conclusions
PTB
PRETERM BIRTH
Cervical length CL ≤ 25 mm measured by transvaginal ultrasound in the second trimester should be used to predict spontaneous preterm birth < 34 weeks of gestation. The NNS is considered low and acceptable and should underpin the implementation of the TVU as a mid-trimester screening test. Women with CL ≤ 30 mm can also be considered at higher risk for PTB in the Brazilian population.