Are Weighted Blankets All They're Cracked Up to Be?
MYTHBUSTER: Weighted Sleep Sacks/Blankets are Safe for my Baby!

Not always! Let me explain a little bit. I worked in Early Intervention for years and learned a lot from my physical therapist friends and I've done my own research. Here's what I've learned:
The market is saturated with weighted sleep sacks and it's originator- the Merlin Sleep Suit- was the first to introduce the idea of something weighted to help your little one sleep better.
But the research isn't clear that these are really recommended- the American Academy of Pediatrics and some well known pediatricians DO NOT recommend these blankets.
Here's Why:
When babies are little they need their startle reflex- better known as the Moro Reflex- to help them understand when they are in danger. It developed eons ago to help babies respond to their fight or flight reflex.
If they were in danger they could startle themselves awake. But when you add weight to their little bodies, YES it helps them sleep better because they are snug and weighted down BUT that's not always what you want for your little ones.
You want them to learn how to sleep with their reflex which they will learn to do with a tight swaddle.
When they outgrow their swaddle it's best to transition them to a regular sleep sack. One big reason for this is that they will have to wean off of a weighted sack at some point and from a child development and sleep perspective there's no time like the present to help them learn how to sleep on their backs in a regular sleep sack.
Yes, it can be a rough few days but they will learn and then you won't have to help them learn it at another time.
If you to help your little one learn to sleep without the swaddle then you can practice one arm out during naps for a few days, and then both arms out, and then into the sack.
Practice at naps so that if they don't have good naps you still have time in the day to get them sleep anyway you can- car, stroller, on you.