The device used to test Georgia's blood is an Epi-Pen trainer.
In the movie, Arthur refers to Karel Capek and his 1920 play R.U.R. - which is about a class of artificial 'human' designed for labor that revolts to end the human race.
The dagger used by Arthur is actually an Austin Moore prosthesis used for hip replacement surgery.
To prepare for her role of an expectant mother, Chloë Grace Moretz consulted several pregnant women, even attending a Lamaze class and visiting a hospital maternity ward. She even volunteered at a private day care center to learn proper child care, though changing diapers was her least favorite.
Netflix acquired the international streaming rights to the film and it is scheduled to be released in all other regions on January 7, 2022.