Don't. Just don't.
It's a common phrase that pregnant women hear from other people, "He'll come out when he's ready." But personally I find this unsupported and insensitive. Hear me out.
I think this is an insult to every mom who experienced delivering premature babies, especially those who lost their babies because of premature delivery. I highly doubt it's any baby's intention to escape from its mother's womb at a time when they can't even breathe outside it. The popularly used line is also an insult to moms who have to endure the time to wait until their baby is well enough to be discharged from the NICU, because the baby needs antibiotics to cure the infection from pooping in the womb because they were way mature but overdue.
He'll come out when he's ready. Pshh, no, it doesn't make any sense.
Every woman is unique, every pregnancy is different, and unless you're delivering via scheduled c-section, you don't know when you're baby is going to make its appearance in the world. My two cents: if you hear a pregnant woman complain about how long they're been waiting to give birth, or say I'm just so doooone, or say they want the baby out now, just be emphathetic. Not assuming, not stupid.