A woman who donated her eggs to another woman in order to create a baby via the in-vitro-fertilization process. An egg donor. A play on words to differentiate the mother i.e. baby-mama and the father i.e. baby-daddy and the egg donor i.e. baby-dona.
I am not the baby-mama I wasn't pregnant with the baby; and her husband is the baby-daddy because he provided the sperm; I am the baby-dona because I donated the egg, which combined with the sperm to make the baby she gave birth to.