I was recently asked the question as to whether baby necklaces are actually safe for babies. As with most baby jewelry, my answer was "with supervision."
To clarify, if baby is going to be with adults the entire time she's wearing her baby necklace, there is no reason to be concerned. It's when baby is sleeping, in a separate room to her mother or carer, that problems can happen. Some babies are surprisingly strong. If she gets her hand or arm caught in her necklace, she can break it. Furthermore, if the necklace she breaks, is made up of beads or other items of swallow-able size, those beads can end up in her mouth and she can choke.
Baby necklaces are meant to be worn on special occasions where she has an adult with her at all times, when photographs are being taken and she's looking her best. For extra safety, ensure the necklace is only 12" - this decreases the likelihood of her catching her arm in it and breaking it. Her baby jewelry is most especially to be worn for her baby portraits, but when she's put down to sleep, please remove her little necklace and keep it in a safe place (preferably her own little children's jewelry box.)
Baby bracelets, and necklaces in particular are for showing her off at her best and recording her image on camera. After she has grown out of her necklace, and this goes for all baby jewelry, keep it for her until she's grown up. She will marvel at how tiny and beautiful the item is, that she wore as a small baby.