That's not to say that they won't munch on them. My DS has his in his mouth almost constantly, and reaches under his clothes to get at it. Because of that, he sleeps during the day with it on, but not at night. My concern is that he'll weaken the cotton enough to break it - although they are knotted at each bead he could still swallow and/or choke on one bead at the break point if it breaks whilst in his mouth - even though this is really unlikely, if it happens, it's probably best that it doesn't happen at night where I may not hear him if he chokes. If your baby doesn't touch it or put it in their mouth, then it's highly unlikely that harm could come to them if they wore it at night, they are designed to either break or for the clasp to come undone if undue pressure is exerted on them.

The compound in amber is succinic acid (Baltic amber has the highest concentration of this, which is why you should choose Baltic amber for pain relief), which was used in regional traditional medicines - by melting and infusing the amber. Although a fair amount of research was done in the early twentieth century on the medicinal properties of amber (it is confirmed that succinic acid is an anti-inflammatory), there has been no research confirming that amber releases succinic amber at body temperature or indeed whether it is absorbed by the skin. However, there is a vast body of anecdotal evidence to support this.