If exhibited by an expectant father, what is a warning sign of ineffective adaptation to his partner's first pregnancy?

Consistently changes the subject when the topic of the fetus/newborn is raised.

Explanation:

This is the decision of the couple whether they want a child or not and can discuss about the family planning as well. Different psychological aspects acn explain this matter.

The expectant father is not mentally prepared for the child. He might refuse the talks and stay away from the communication that are related to the new born child. This must be properly assessed and important to understand the feeling of the expectant father.  

Thus, the answer is consistently changes the subject when the topic of the fetus/newborn is raised.

this transfer is call conjunction