Especially if she had been planning on coming home for the birth then got stuck in Kenya, Mom might have been planning on putting an announcement in the paper anyway and, under the circumstances, went ahead and did it. Doesn’t explain the fake address, though.
Unless, Mom was trying to hide from people the fact that her daughter was in Kenya with that Kenyan baby daddy, if she was trying to mainstream things for her daughter a tad.
Well, what would a typical white woman do, especially in 1961?