In the Wormwood boss fight in the Antibirth mod, after Wormwood destroys 4 tiles from below, it then bursts out of the upper or lower side of the right or left wall at high speed. Is there any way to tell which of those 4 spots it's going to come out of beforehand?
According to the wiki:
After a short delay, he will break through one of the walls to the left or right and charge at Isaac at a high speed.
So there are no direct indicators to help you know which area it will come through and you're left to guess. However it does say that Wormwood's attack patterns are similar to Pin's attacks so that may be of some help to you.