What size are the Birth Posters? We offer the Birth Posters in 2 sizes: The size of the Solo Baby and Duo Baby Poster is 50x70 cm (19.7”x27.6”) The size of The Trio Baby Poster is 100x70 cm (39.4”x27.6”). Related articles Paper, sizes and formats of design posters What is a Birth Poster? What is the paper quality used on Birth Posters? Does the poster come with the frame? What is a design poster?