Reference range for the pulsatility index ductus venosus Doppler measurement between 11 and 13+6 weeks of gestation in a brazilian population - Peixoto, Alberto Borges; Caldas, Taciana Mara Rodrigues da Cunha; Martins, Wellington de Paula; Ferreira, Polyana Costa; Nardozza, Luciano Marcondes Machado; Costa, Fabricio da Silva; Araujo Júnior, Edward (The Journal of Maternal-Fetal and Neonatal Medicine, 2016)