Need advice!:

Carla • In love with my little family❤️ | 1st baby due Sept 27, 2016❤️
So my MIL told me I can't lay on my back, because my baby will choke in the womb, is that true?? 😟 She says that's what people have told her. But I'm currently about to be 17 weeks, and I don't know if she means if it's bad when the baby is actually bigger. I don't know how I sleep sometimes at night, but now I'm just paranoid. ☹️