Because 24h without monitoring is not advised, I'm a doctor, you would check for fetal distress (or things like breech position as in Joy who Jill and her "midwive" let Labour for 10 hours and didn't even notice) a long time before that. FYI if you wait too long you can't do an Epidural anymore
The Anaesthesiologist did test her, pricking her arm and then her legs and asked her if she feels any difference. She said "a little" now epidurals are pretty much hit or miss - either you hit the spot or you didn't - dermatomes are a wonderful thing. That's why he didn't do a new one straight away.
You could also give other pain medication before that (they said they gave her a muscle relaxant though I wonder what kind) . Of course her body was already cramped up and labouring for a day without help def isn't advised and of course fucking painful.
She faked migraines before to get out of a fucking game laying down smiling on the sofa right there in the light noisy room - having migraines myself - nope never going to happen
And of course the Duggars have an awful track record for going to the hospital only when shit hits the fan. In Jessas birth episode like Jill she used castor oil to speed up labour. That's a a dangerous old wive's tale - it stresses the baby out and they pass meconium like it happened in Jill's case. Meconium aspiration can lead to life threatening respiratory infections.
Now with pain management you always treat on the side of caution, generally they way the patient subjectively experiences it determines the treatment. Unless the patient is obviously faking - a few choice questions about pain quality exact site radiation of the pain can often tell you.
Graphic added; spinal vs epidural