This study aims to investigate the longitudinal change in visceral fat thickness (VFT) during normal pregnancy. A prospective cohort study with 75 primiparous adolescents was carried out in Petrolina, Brazil. VFT was evaluated by ultrasound between 12–20 weeks gestation and immediately after delivery. We noted a statistically significant increase in VFT; 1.3 cm ± 1.0. No correlation was found between VFT and maternal anthropometric variables. VFT increases about 30% from the first to the second half of pregnancy in primiparous adolescents.