Reference values for the cervical length measurement in the second trimester of pregnancy using the transvaginal ultrasound in a large Brazilian population - Peixoto, Alberto Borges; Caldas, Taciana Mara Rodrigues da Cunha; Alamy, Ana Helena Bittencourt; Martins, Wellington de Paula; Bruns, Rafael Frederico; Araújo Júnior, Edward (Obstetrics and Gynecology Science, 2016)