Effectiveness of cervical pessary compared to cervical cerclage with or without vaginal progesterone for the prevention of preterm birth in women with twin pregnancies and a short cervix : Study protocol for a two-by-two factorial randomised clinical trial

Dang, V Q, Dang, V Q, He, Y T N, He, Y T N, Pham, H N H, Trieu, T T T, Bui, T Q, Vuong, N T, Nguyen, L M T, Nguyen, D T N, Le, T V, Li, W, Le, C H, Mol, B W & Vuong, L N 2020, 'Effectiveness of cervical pessary compared to cervical cerclage with or without vaginal progesterone for the prevention of preterm birth in women with twin pregnancies and a short cervix : Study protocol for a two-by-two factorial randomised clinical trial', BMJ Open, vol. 10, no. 6, e036587. https://doi.org/10.1136/bmjopen-2019-036587