Bring it up again, and after she says 'no' again, just say, 'Alright... just keep an open mind about it... okay?" (Get that 'hang dog' - 'I'm so hurt that I'd cry if I weren't so strong" look as you say it and after.... the whole day, at least. IF you haven't done these expressions at some point... well, nevermind. All is lost!)
Then... don't say a word. Smuggle your Yarborough into the delivery room. As the strong contractions, shouting, shunting you aside begins... and she's all sweaty, drained, probably drugged up, and has that glazed look - ask again, very quickly: "(Your personal term of endearment), is the Yarborough okay?". Chances are, she'll just nod and say (more like grunt) "Okay!" (Which means: "I don't give a shit. Leave me the hell alone. I just want this OVER!)
Make sure this approval is videotaped.
(Remember... I'm divorced.)