Prevalence of Vitamin B12 Deficiency in Early Pregnancy and its Association with Preterm Birth: A Prospective Cross-sectional Study. Global journal of medical and pharmaceutical sciences, [S. l.], v. 3, n. 5, p. 17–22, 2025. Disponível em: http://www.globapc.com/index.php/gjmps/article/view/108. Acesso em: 24 oct. 2026.