What is the ruling of Islamic law regarding a man retracting his oath not to have his wife travel with him, given that he swore by divorce if she went with him, and she is still pregnant?

Divorce occurs when the wife leaves with the husband, according to the majority of jurists, whether she is pregnant or not. The husband may take her back if she is within her iddah (waiting period). Sheikh al-Islam Ibn Taymiyyah was of the opinion that divorce occurs if its occurrence was intended, and does not occur if the intention was merely to threaten. The preferred view is that of the majority.