Probably by its name.
English doesn't really have a special word for this particular relationship. If for some reason you feel it's important to designate your precise status vis-a-vis such an individual, then "my god-daughter's baby" is probably as good a phrase as any.
Le mie figliocce is an Italian equivalent of the English phrase "my goddaughters." The feminine plural phrase may be found commonly misspelled as le mie figlioccie even by native Italian language speakers. The pronunciation will be "ley myey fee-LYOT-tchey" in Pisan Italian.
in France you call baby- bebe.
cameil is how you call a baby camelion
The Godfather of anime , Osamu Tezuka's children would be referred to as his Godchildren (Godsons and Goddaughters).
I would call it what you call every spider which is a spiderling
You call your daughter's baby, your grand-duaghter.
You call a baby moray eel an: elver
"Just call", by Sherrick
You could call it a mermale or a mer-baby-male
You call any baby deer a Fawn male or female.
Heather will call her baby George! xx
baby panda