Pregnancies can be amazing and fun, but they are also uncomfortable. Your body is changing; your belly is growing, your hips are getting wider and topping it all, your hormones are all over the place!
That is enough discomfort. The last thing you need is to have a rough time sleeping.
Besides, discomfort for you means discomfort for the baby!
Your usual sleeping positions will get more uncomfortable as the baby bump grows. You need something more pregnancy-friendly.