I'm often asked about safety and comfort when it comes to purchasing a piece of baby jewellery. Baby Jewellery these days is about as safe and comfortable as possible, however, I always say "supervision" is the key word here.
Baby brooches are great, provided the clip/clasp/pin that used to attach to their clothing is very strong. Babies have surprising strength and are capable of pulling off a poorly made brooch. So, providing they are well made, I would recommend a brooch.
Baby bracelets are probably the most popular item but they are not the safest. Babies should be dressed in bracelets only if they are going to be supervised. The bracelet should be removed before baby is put down to sleep. Catches should be strong for the same reason brooches should be well made. Charms look divine on little roly poly wrists, but if they are not strongly attached, they could be pulled off by a little hand and popped in the mouth. So supervision with bracelets at all times.
Bangles, plain solid bangles, are the safest. With no moving parts, nothing to pull off, provided they are properly fitting, baby can do herself no harm. Otherwise, the same applies to baby bangles as baby bracelets.
Baby earrings are safe provided ear piercings are well healed and the backs (or nuts) are firmly fitting. Earrings sit on a baby ear lobe unseen and unfelt so are unlikely to be even noticed by baby.
Similar to bracelets. Can get caught on something and broken or tugged off.
Supervision at all times. Baby might be aware she's wearing it and pull at it, at least until she's old enough to lose interest in it and knows not to tug on it. Still, supervision can't be beat!
Baby jewellery looks divine when worn by little people for special occasions, the family photos or her first baby portrait, where they are preserved forever. But generally, comfort and safety should be kept in mind.