I see a lot of posts on this app about:" Could it be twins", "maybe more than one sac", and other things like that. Please remember that every baby is a blessing and is special.. Im just as grateful about this baby, as I was when having when I was having twins. They are NOT any distinctive symptoms either. Also, with technology as advanced as it is, its VERY UNLIKELY they could miss another baby. Just like they tell you whether or not you're pregnant, they will also tell you if you're having more than one baby, you wouldn't have to guess. (Not try to be "judgmental", just expressing myself as a mom of twins and a mom of a singleton.) Congrats to ALL mommies! :-)