Wiktionary
fall pregnant
vb. (context intransitive formal or literary English) To become pregnant.
Usage examples of "fall pregnant".
Her best hope would be to fall pregnant, and win the loyalty of one of the men.
She had aided Faraday in her determination not to fall pregnant to Borne-held - Mother knew she could not wait to see the end of the line of the Dukes who had cursed her.
For a young woman who was unlucky enough to fall pregnant without a husband on the horizon, there was little choice.