During pregnancy, pelvic organ prolapse is uncommon and is associated with adverse outcomes such as vaginal infection, cervical ulceration, and preterm delivery. Treatment includes conservative and surgical management during pregnancy. A 32-year-old woman presented with a history of vaginal delivery eight months earlier reported the sensation of a vaginal mass lasting seven months. On physical examination, we noted pelvic organ prolapse and 19-week pregnancy. We treated her conservatively with a Gellhorn pessary and antenatal corticosteroid for fetal lung maturation at 32 weeks due to a high risk of preterm delivery. The pregnancy proceeded with no obstetric complications and vaginal delivery at term of a healthy neonate. Conservative management for patients with pelvic organ prolapse during pregnancy using a pessary is the best option to improve maternal symptomatology and minimize gestational risk; there is no contraindication for vaginal delivery, and cesarean section is reserved for obstetric indications.