John Lydon aka Johnny Rotten was brought up Irish-Catholic and always said it was not pro or anti-abortion. His point was more to do with the incredible irresponsibility of the people involved. In my view it is very much an anti-abortion song.
If you watch their video The Filth & The Fury - Lydon was a very stealth anti-Labour and pro-Thatcher Brit. Their songs largely had to do with incredible hypocrisy and were more libertarian.
She was a girl from Birmingham
She just had an abortion
She was case of insanity
Her name was Pauline, she lived in a tree
She was a no one who killed her baby
She sent her letters from the country
She was an animal
She was a bloody disgrace
Body! I’m not an animal
Body! I’m not an animal
Dragged on a table in factory
Illegitimate place to be
In a packet in a lavatory
Die little baby screaming
Body screaming f***ing bloody mess
Not an animal
It’s an abortion
Body! I’m not animal
Mummy! I’m not an abortion
Madonna and ELO also did.