Early vaginal progesterone versus placebo in twin pregnancies for the prevention of spontaneous preterm birth: a randomized, double-blind trial

Anoop Rehal, Z. Benkő, C. de Paco Matallana, Argyro Syngelaki, D. Janga, S. Cicero, Ranjit Akolekar, Mandeep Singh, Petya Chaveeva, Jorge Burgos, Francisca S. Molina, Makrina Savvidou, María de la Calle, Nicola Persico, Maria Soledad Quezada Rojas, Ashis Sau, Elena Greco, N. O’Gorman, W. Plasencia, Susana Pereira, Jacques Jani, N. Valiño, Maria del Mar Gil, Kate Maclagan, Alan Wright, D. Wright, K. H. Nicolaides