The expectant couple obtains some special wood and burns it down to ash. Traditionally, the desired wood leaves white ash, because it will make the rest of the spell easier, however this may be adapted to suit specific desires. Any traditional magick wood, such as birch, ceiba, hazel or rowan would be appropriate, too.
These ashes are reserved until the birth.
After birth, the placenta is carried to a strategic area, traditionally a mountain crossroads, and placed on the ground.
The ashes are sprinkled onto the placenta.
The first animal to leave prints either in or with the ash is the child’s protector or represents the species.
Of course, this spell obviously derives from a rural area, with little traffic but a lot of wildlife. Adapt to your needs.