Here is the thing. Piercings do not heal like a normal wound would.
The body wants to reject the foreign object. This is why piercing healing time is so long. I have had piercings that took up to 2 years to heal. And as I already stated, my ear piercings from when I was a baby NEVER healed. It is not just the injury of the piercing you must consider (it IS an injury - you are poking a hole through a part of the body), but also the months and maybe years of healing time thereafter, likely with repeated infections because she, being a baby, doesn't comprehend that piercings need care. She is not going to think "oh, I need to clean my piercings!" after getting dirt on her face.
But all of this is beside the point that it is completely non-consensual. Caring her for her in necessary ways - food, water, shelter, love, learning - are necessary. Punching holes in her body are not. It is altering her body in an obvious way that is unnecessary without her consent.
If your wife decides to do this anyway, PLEASE PLEASE PLEASE tell her to go to a proper piercer. Don't let her get the piercings done with a piercing gun. They are dangerous, unclean, and cause more tissue damage than is necessary. The earrings are of cheap quality and often break down when in contact with the body fluids produced during healing. They have even caused outbreaks of Hepatitis.
Please tell her to see a professional piercer who has the proper certification in your area, and who uses an AUTOCLAVE for all re-usable equipment, like forceps.
...I am not normally one for so much gratuitous bolding, but in this case I feel it's necessary.