Baby Congratulations Phrase Is It Bad Etiquette To Send A Congratulations On Your New Baby/Merry Christmas Card?

Is it bad etiquette to send a Congratulations on your new baby/Merry Christmas card? - baby congratulations phrase

A former colleague of mine who lives in another city, a baby a few weeks ago, and I wanted to send a Christmas card in a few weeks, but I want something on the card to congratulate her on her new baby to write. Is that bad manners? Should I have separated the cards? What do you suggest?