Le KD, et al. - The cost-effectiveness of cervical pessary vs vaginal progesterone in preventing preterm birth and neonatal morbidity in women with a twin pregnancy and a short cervix is investigated. This economic analysis was conducted between March 4, 2016, and June 3, 2017, following a randomized controlled trial, conducted at My Duc Hospital, Ho Chi Minh City, Vietnam, that compared cervical pessary with vaginal progesterone in women with twin pregnancy and cervical length < 38 mm between 16 and 22 weeks of gestation. Morbidity-free neonatal survival was used as a measure of effectiveness. Screening of 1,113 women with twin pregnancy was performed during the study period; of these 300 fulfilled the inclusion criteria and were randomly assigned to receive cervical pessary (n = 150) or vaginal progesterone (n = 150). Outcomes revealed a significantly improved rate of morbidity-free neonatal survival in women with twin pregnancy and a short cervix in correlation to using cervical pessary while reducing costs, as compared with vaginal progesterone.