Parents who experienced baby loss, how do I acknowledge a lost baby respectfully?

I have a dear friend who last year lost a baby at 20 weeks old pregnant. She was soo excited about that little one and lost them right between Christmas and New Years. She is pregnant again and I want to buy/make her something not only for this baby, but also for the one before. I was thinking of a necklace/bracelet with two babies, but then I thought that will maybe make her upset or maybe people would ask why are there two since she has only one. She doesn't speak about the baby at all, so I am not sure if she wants to burry that event in the past. Any advice?