In the United States, one says, she is pregnant BY him...
In Ghana, one says, she is pregnant FOR him...
This may be simply a random twist in syntax, but to me the different prepositions carry different connotations. To be pregnant BY someone seems more to imply that the man is the subject and the woman the object, while to be pregnant FOR someone seems to imply more agency on the woman's part; she is the subject and he the object. In addition, to be pregnant FOR someone suggests that a woman is doing a man a favor by carrying his child.
I'm warming up to the use of "FOR" in this case.
I have worked in economic policy and research in Washington, D.C. and Ghana. My husband and I recently moved to Guyana, where I am working for the Ministry of Finance. I like riding motorcycle, outdoor sports, foreign currencies, capybaras, and having opinions.