A Yorkshire joke. To understand this, you need to know in Yorkshire 'Coal' is pronounced 'coil'.
A pit is known as a 'coal hole', pronounced 'coil oil'.
Anyway...
Barnsley miner, Alf Sidebottom, gets home from a hard days work at the pit. On getting in the house, he notices the washing hasn't been done, there are dirty pots in the sink, and ironing waiting to be done. The wife is upstairs in bed. So the miner shouts up to her...
Miner: "Na then tha lazy cow. Ant tha dun any work today?"
Wife replies: "No luv, am in bed. Am not very well."
Miner: "Whats up wi'thi luv?"
Wife: "Bit a woman trouble... you know luv, down there..."
Miner: "Oh. Right. Ad berra fetch't doctor then."
So the doctor arrives and the miner explains the wife has a bit of 'woman trouble'. Anyway, the doctor examines the wife and reports back to the miner.
Doctor: "You were right Mr Sidebottom, it was 'woman trouble'. She hadn't got her coil in."
"Ant gorra coal in?" The miner says, "She ant got f****n' tea ready yet..."